Some are good, others probably not.

Both sprite reskins are alright. Would we craft them via the sanctuary alchemy machine with the standard pet? I would say we should need up to 3 of the corresponding materials for these. If they come out of a "shadow lair"-esk promo when we get further into the core, that might be a better course of action as not to make snarby and gun puppy sprite owners get a kick to the teeth.

Shield-wise, I'm going to give quick guesses to crafting lines:
Ice Queen Shield - Rock Jelly Shield. Would be an okay split as we are lacking pierce + status shields.
Rabid Thorn Shield - Dark Thorn Shield. Reduce sword damage to low and lower piercing resistance (as you suggested), and this is good.
Mercurial Shield - Rock Jelly Shield? Might be good to have a full shield line from the bark modules.
Cursed Plate Shield - Heavy Plate Shield. Seems good. However, maybe make it in the divine scheme and call it "Blessed Plate Shield", or "Pure Plate Shield"

Each of these items requires a 5* shadow lair material of the appropriate boss.

Now to weapons. Going to give a similar thought as I did above:
Almirian Spear - Grand Flourish? Should have it's own line if anything. I'm against any flourish being in different damage types personally, but those are my thoughts on the weapon.
Cryocore bomb - Master blast bomb? Should branch off the blast bomb after 2*. Sorta iffy on whether we need this.
Rabid Snable Blade - Dark Thorn Blade. Similar tradeoff as the shield, and the status flourish lines.
Rabid Briar Barrage - Spike Shower. Similar tradeoff as the shield.
Fission Power Core - Heavy Crystal bomb. Similar trade-offs as many other shard bombs, not a bad idea.

All these ideas are solid. I am just personally against shadow flourish and on the wall about the cyro bomb, but that's more a me thing. They aren't completely out of place in the game, and could blend well into it.

Keeping balance with the other snarby shield is sorta needed. You're adding poison resistance to the shield, and taking away defense on the shield really will just make this shield a better version of the other one. Defense on shields has been shown to have a much lesser affect opposed to status, thus adding a full status should warrant taking away at least one half of the damage bonus the other shield has.

If +Poison resist wasn't such a big deal I wouldn't mind keeping damage medium, however +Poison resist is a pretty big deal, thus lowering your sword damage by 4% makes you actually weigh in the options (are you using this shield for offense, defense, or a mixture of both?) rather than just picking the obvious upgrade.

Yeah, I was thinking more in terms of game balance. We do lack in shadow swords, but I would rather see something new in a pure shadow sword than reskin a flourish. One reason being because then we'd have shadow flourish strikers in lockdown and instead of the flourish counter being piercing resistance now you have to deal with a shadow one too.

If we were to get a sort of heavy piercing weapon like a lance, I would be all for a piercing and shadow version of that, as that's how the dreadnaughts have been going with us for a while. However I do see the appeal in a shadow flourish too as crusaders have those... But that might just be because they are cursed souls, not necessarily a shadow-tipped blade.

And I think a problem with a shadow flourish is that the acheron does still outdamage it. It doesn't have some niche to fill like the rocket hammer does, and single-target no-knockback strikes (what flourish-line weapons specialize in) just aren't that effective against slimes and gremlins. I would rather see a shadow cutter than a shadow flourish, as they both fill a role of fast-single target weapon, but cutters at least drag enemies away from each other.

Cryocore bomb dealing freeze and knockback is the only part that makes me iffy. We have the same problem on the permafroster, plus the only bombs that deal status outside of haze bombs are shard bombs and blast bombs that deal stun. I'd like to see it in action before I make too big of an argument for or against it though...

Fission Power core is just something we should've had from the start. No need to give elemental shard bombs the short end of the specialist stick.

Thing is we have quite a few status blast bombs that are 1*. They are meant to sort of get players thinking about bombing. My only thoughts are why a bomb would both push back and deal piercing damage, then freeze on top of it. I mean, I like the idea mind you, but those three combined don't really make sense to me.
Knockback + freeze creates a sort of unhelpful situation, as you can't choose when you freeze an enemy, so they're either going to be away from you or stay right next to you. Piercing + knockback doesn't make sense from a logical standpoint (hence why DBB has no knockback), but I can look past that from a design standpoint.

Using the gunner update to say "anything is possible" is not really a valid argument. Guns needed a buff, and they got what they needed. Blasters are universally helpful, being reliable weapons with a slight knockback. From a logical standpoint yes, it makes no sense. Game design standpoint, I see exactly why they did what they did. Making leviathan blade and nitronome into the same sort of thing would be a similar situation, not being too logical but making sense to game design.

Now let's just take a quick look at shadow-weak enemies. Gremlins and Slimes. Both have a tendency to swarm you, and are dangerous to be close to.
Slimes are dangerous because of their 360 degree attack, and long tackle range. Gremlins are dangerous at close range with their melee attack, and if three thwackers are around you, it's gonna hurt. Both gran faust and the nightblade weapons deal with such enemies, knocking them back. The nightblade lines also have a good single-target ability, although it's not as fast as it could be.

With this in mind, we can look over at flourish attack patterns again. Flourish has a wide first hit, and two accurate stabs forwards for second and third hit. The charge attack is inverted.

The weapon should be useful if someone is playing by the most basic means - i.e., full combos on enemies, charge attacks at critical moments. On slimes, the combo will not be helpful as slimes do not retreat and do not move all that quickly. On gremlins, the combo will be helpful, but gremlins have a tendency to group up and attack in droves, which means going after that one gremlin will draw you into the horde of gremlins, and you're get a thwack hammer to the face.
Now the charge attack - an inverted combo. This will be helpful against slimes, however the combo leaves you in the thick of the enemy - meaning their 360 degree attacks are going to come crashing into you. Similarly with gremlins, you might take out quite a few of them, but if you missed any you'll get a face full of hammer.

A flourish is designed to seek and destroy single targets quickly. Both monster families weak to shadow group up and attack in unison. The current enemies weak to pierce (and thus the flourish) split up or do not track you with attacks, such that you can pick out an enemy in the crowd and single them out, pushing them out of the crowd. They also dodge or try to get out of melee range, which the flourish helps cover the distance for.

I guess what I'm saying is, in the end, a shadow flourish has a similar situation to a piercing brandish - both weapons are already good where they stand, however if you throw another damage type onto it the weapon will actually lose efficiency because of what its attack style is intended for.

TL;DR - I give an essay on why I said the other things in my other posts.

Ice Queen Shield (Stun/Ice/pierce resist)
Mercurial Shield (Shock/Pierce resist plus ASI low)

+1
Couldn't agree more, we definitely need these :3
Although having them accompany a Royal Jelly Line buff (like with Universal CTR: Low per piece, including the shield) would be awesome

Cryocore bomb (Pierce/Freeze Blast Bomb)

-1
I know that we don't have any pierce freeze weapons, but making another blast bomb, especially a normal damage or pierce blast bomb doesn't really help the lack of diversity in bomb types. Elemental would be preferable (since we don't yet have an elemental bomb) but a Shadow Freeze bomb would fill a hole in our bomb tree.

Almirian Spear (Shadow type Flourish)

-1
I know that our diversity in Shadow swords is also pretty miserable, but c'mon, you coulda thought up something better than just a "toothpick reskin", seeing as there have been some great lance suggestions.

+1
Rabid suggestions are great, but the Rabid Snarbolax Sprite is already in the game.

We don't always have super good weapons, but for the most part what you're pointing out are statuses on weapons, not the weapon themself.
Furious Flamberg has piercing damage, thus its attack style still matches the damage type. Freeze weapons in general are going to break their own freeze if you attack without restraint as that is how freeze works.

With all three freeze weapons you state, if you use the weapon as a freeze tool (i.e., single shots at a time), then freeze will be more reliable. If you use the weapon more optimal to its actual weapon stance (charge attacks on hail driver, bullet spam with permafroster, single target firing or crowd control charges with the winter's grave), then for sure you're going to lose out on the status because you're prioritizing damage.

In the case of a shadow flourish, we aren't just tagging a status on a weapon that works on those monsters, you're taking a weapon that already fits its niche perfectly and throwing it into a spot where it will do poorly. An elemental flourish would perform better, but again, those monsters can group up a lot and rely more on knockback or critical hits rather than chip damage. An elemental flourish would definitely fare better than a shadow one, but I feel we should keep the flourish piercing. A sort of heavy lance would be a great weapon for shadow damage. You could have the standard variant inflict fire, and the shadow lair version curse... How it would perform is for another thread though.

Piercing + knockback doesn't make sense from a logical standpoint (hence why DBB has no knockback), but I can look past that from a design standpoint.

If you're going to quote me, try to quote the whole thing. Game design should trump logic in almost all scenarios, unless the game design is to make the game as realistic as possible... Which is still game design trumping logic technically.

Freeze and knockback are opposites. You either are relying on one or the other - never both. When using a permafroster, you are trying to knock enemies into corners, not freeze them in place. When you use winter's grave, you use the charge attack to dig through crowds of enemies and deal damage, and any freeze to come out of it is a size-effect. If you attack head on with the winter's grave, you'll likely even want the enemy to not get frozen along the way.
Now let's take into effect the sort of monsters that will be affected by a piercing bomb - beasts and fiends. They are both definitely enemies that like to be around you, but in the case of fiends, typically not too close to you. Both of these enemies are devastated by our favorite piercing bomb, the Dark Briar Barrage. This is in part because of high knockdown rather than knockback.

Now let's look at a piercing freeze knockback bomb. Piercing damage deals effective damage, then knocks enemies out of range. In the case of fiends, you'll be pelted by projectiles, or with beasts, they will just teleport behind you, making knockback on these enemies a moot point. Second, an occasional frozen enemy will not save this bomb's potential, as keeping an enemy in range based on RNG is not going to fill any role that DBB or a shivermist already fulfills.
This bomb is trying to be a hybrid, but doesn't fix much of anything. It would only be useful on enemies that are large with high knockback resistance that also are weak to pierce... Which is pretty much just trojans and Vanaduke.

We've seen freeze and knockback combined fairly recently, and it just isn't a pretty sight. Knockback and piercing is better, but also still a bit of awkwardness to them (many piercing weapons don't deal knockback. See: flourish, blitz, antigua, DBB. Of the weapons that do deal knockback, how effective is that knockback attack on the enemies it's helpful against?)

Sorry that I'm writing essays on this, but all the tidbits of that bomb idea work against each other. It might be helpful in lockdown, and it would be a nice alternative to a shivermist for FSC, but other than that it really has no purpose design-wise.

TL;DR - Blast bombs are keep-away weapons. Freeze is a stand still status. Merging the two against fiends and beasts ends in frustration and sadness, except for Vanaduke and Trojans.

@Holy-Nightmare
In post #9 I proposed an alternative to the freeze pierce bomb

What was the alternative proposed?

@Fangel
I have to disagree.

The issue with the freeze on existing knockback weapons is it often interferes rather than assisting with the weapon's strongest points:
1. For the Triglav, which has massive knockback on the second swing, and on the charge attack, this knockback used to protect the user from future attacks, is cancelled by the random freeze. A full combo or a stomp charge puts you blatantly in range of frozen enemies. (but you're safe using a blast charge, Lumbers excluded)
2. The freeze on the Permafroster interferes with its primarily-utilized ability to combo-knockback enemies efficiently into corners and walls.
3.On the Winter Grave, freeze is great on the regular attacks as it allows to get more bang in for your buck. On the charge though, it's only really useful for stationary enemies, as otherwise the freeze interrupts the massive knockback. I guess it could still be utilized for randomly freezing enemies, and clearing the rest of the enemies who weren't frozen out of the way.

The knockback from Blast Bombs is arguably far less simple and less predictable to utilize regularly:
1. Unlike the Troika's charge, the Blast Bombs do not cause massive increments of knockback.
2. Unlike the Pulsars, it cannot be rapidly and easily chained in a very short period of time.
3. Unlike both of the above, it knocks multiple enemies in multiple different directions.
4. Unlike the Magnus, mobs can have moved out of or into the area of effect between releasing the charge and the knockback being dealt, and are not highly likely to be sucked back from their target (unless you're standing right where the bomb is planted when it goes off)

Both of these enemies are devastated by our favorite piercing bomb, the Dark Briar Barrage. This is in part because of high knockdown rather than knockback.

This is because these two enemies are programmed with low flinch resist, so while this statement may prove that piercing works well with no knockback, it does not say anything for no knockback working well with freeze.

Now let's look at a piercing freeze knockback bomb.

How about let's not, we don't need any more piercing bombs yet when we still are in need of Shadow and Elemental DPS bombs that aren't shards, DLC, or a gun.

When you use winter's grave, you use the charge attack to dig through crowds of enemies and deal damage, and any freeze to come out of it is a size-effect. If you attack head on with the winter's grave, you'll likely even want the enemy to not get frozen along the way.

Exactly: so why wouldn't you apply this same mentality to using a freeze knockback bomb?

A DPS Freeze Knockback would fill a niche that Shiver does not: and that is dealing damage + knockback at a distance over an area (i.e. the Bomb version of Glacius) Main intention being to deal damage, freeze being a bonus to allow the occaisional twofer, and to reduce the number of monsters sprayed into teammate's faces. Knockback being there to fall back on when mobs aren't flinched nor frozen. This is what makes the Cold Snap so awesome.

I thought you meant an alternative bomb, not just scrapping it altogether. Pierce Freeze sword though. There are a good variety of both status and damages across the gun tree, but swords are really lacking in both freeze and piercing weapons. Rather than just reskinning flourish again though, cryo-force lance....

BLAH, THAT'S IT! I'M SICK OF suggesting weapon ideas without artwork.

Graphics mean a lot.
Not suggesting another piece of equipment without scribbling up what it'd look like first.

as someone who stupidly restricts himself to using only freeze-inflicting weapons, i would trade my left pinky for a damaging freeze bomb