Gloaming Rabid Woods and the Ice Queen Palace are pretty easy once you know the layout. Darkfire Citadel can be easy or difficult mostly depending on what your team is like, but if with the right gear and strategies it's actually easier than regular Firestorm at times. The only SL I would actually say is "hard" no matter what you do is Munitions, mixture of two of the most dangerous status in the game backed by a lot of enclosed rooms, plenty of Rocket Puppies, status slimes and Retrodes and all in all it's just extremely difficult for the unprepared.

If you're planning to bomb in the lairs then first of all you need to forgo the idea of using Mad Bomber. You can get away with it in Rabidwoods and IQP solely because resists don't really make a difference, but short of double Fire/Shock MAX UVs it simply isn't worth it in the other two lairs, you'll spend the whole time fighting with status. Ideally a Volc Demo set with Shock Max on each piece would cover you for both of em really, probably the demo set you could have for lairs. As for your gear set-up my advice would be;

All lairs
-Full Volcanic Demo
-2x Penta Heart Pendants (If you're purebombing, if you have a sword or a gun you can take appropriate bonus trinkets if you want)
-2x Elite Boom Module (IQP if you're using Dark Retribution)

Rabidwoods
-Dread Skelly Shield (CoA is a reasonable alternative)
-Voltatic Tempest
-Nitronome / Big Angry Bomb
-Stagger Storm
-Flourish-line sword / Dark Briar Barrage

All in all rabidwoods is relatively easy to bomb in as long as your team is prepared, everyone else should have one gun at least in order to surpress Howlitzers but other than that your main goal is to status things and occasionally blast-shield in a few rooms (The four gate room near the end of the first level is a good example of a place this helps). A lot of inexperienced people will tell you to take DBB, whilst it works if you think you're going to be dpsing a lot, if you bomb in lairs frequently you'll very quickly find that bombers are much more useful for utility roles than straight up-damge (IQP nonwithstanding) and for that reason I don't suggest it. Although if you're determined to pure-bomb then taking DBB over the fourth slot is fine, even if I really don't recommend it simply because the boss isn't bomb-friendly at all.

Ice Queen Palace
-Ironmight Plate Shield (Aegis or Lionheart work too, you're pretty screwed as far as decent piercing shields go)
-Dark Retribution / Graviton Vortex
-Ash of Agni
-Venom Veiler
-Nitronome / Big Angry Bomb

Not unlike regular RJP, this lair is the most bomb-friendly and probably the place you'll get the most praise for bombing in. DR tears things apart, Ash spreads a fair bit of damage quickly whilst also rendering Ice Cubes almost entirely harmless and VV keeps healing at bay and will also really make people happy since IQP is notorious for being full of hard-to-see projectiles and mini-jellies that hit people a fair bit (I'd say on average 90% of the damage I've ever taken in IQP has been polyps and minis I couldn't see) and VV really mitigates that. Blast-shielding isn't as useful in IQP admittedly but there are a few rooms like the very final fight before the queen herself that it helps out in, so it's worth bringing. I would like to add that if you don't have a Dark Retribution you're going to basically lose a ridiculous amount of potential-dps, and as a result you'll probably want to replace it with either another status bomb (Tempest and Stagger both work well in IQP) or a vortex.

Redclaw Munitions Factory
-Grey Owlite Shield
-Shivermist Buster
-Venom Veiler
-Nitronome / Big Angry Bomb
-Glacius / Dread Venom Striker / Dark Retribution / Graviton Vortex

RMF is by far the hardest lair, the least bomb friendly and honestly I don't ever suggest bombing here. But since you're doing it anyway you need to understand a few things;
*If you don't have a gun, you cannot do anything against Rocket Puppies. It is imperative you let your team mates go ahead and deal with them or you're going to die, waste health and not contribute anything
*You will not be able to touch the twins without a sword or gun, so if you're dedicated to purebombing you're going to want to use Shiver to keep the Scuttlebots at bay and let the rest of your team handle switches/dps.

Those two important details aside Shiver and VV are your go-to tools for this place since Shiver will keep Oilers put-out and will ensure that the slimes and mecha knights aren't running rampant on your team, combo it with Venom Veiler and you've reduced any damage risk and also bolstered the charge attacks your team should be delivering (Glacius is the recommended swordie weapon, if you're a gunner Hail, Nova or Umbra). Your real objective throughout this place is going to be to keep things getting hectic and making sure your team isn't at risk, although bringing a blast bomb is pretty much imperative (Like in every lair) since if things go awry you'll need it to save yourself, and on the odd ocassion shield (Although RMF is uniquely the stratum I think shield is rarely useful over just status-spamming). If you aren't bringing a sword then Dark Retribution is a fine dps weapon to soften up the abundance of constructs and slimes you'll encounter and it works well with Shiver & VV, if you don't have DR and still don't want to bomb then vortex is a good alternatively but make sure you use Graviton, Electron will run the risk of setting off Quicksilvers and shock is generally bad in here due to all the switches.

Darkfire Citadel
-Crest of Almire / Volcanic Plate Shield
-Shivermist Buster
-Nitronome / Big Angry Bomb
-Stagger Storm
-Blitz Needle (If you insist on pure bombing, Venom Veiler or Voltaic Tempest)

Honestly bombing DFC is a pain. Lots of Howlitzers, no effective Elemental-dps bombs since the shard change and obviously vana himself is immune to Shiver, which makes the main role bombers have in the fight completel moot. Beyond that Canavrons don't really get decimated anywhere as easily as regular zombies do by vortex, which makes you probably less than half as useful as you usually are in fsc, which all in all isn't great. First thing to accept is that trying to dps is basically pointless, the best you can do is DBB-spam which isn't going to contribute much besides making everything hard to see (Unfortunately most of DFC blends into DBB blasts) and as such you're pretty much support-only. Shiver and Stagger are going to be your main weapons throughout the citadel, locking down Canavrons and more importantly Trojans and Slag Guards is going to make the run a lot smoother. Your whole team should be packing Blitz Needle really, but if you insist on purebombing you really need the rest of your team to all take a Blitz otherwise your dps is going to drop pretty horribly throughout a lot of key rooms as well as the boss (not to mention Blitz is the wepaon that combos with Shiver the best). Nitro is a great weapon to have for a few rooms on the third depth since it can clear out Canavrons from an area to give people breathing room (Freezing them too close gets everyone killed) and can also create great safe-areas in the big fights on the branching paths. Just know when you need to status, and when you need to blast things away and you'll be able to support your team fine in the citadel. Once you get to vana, assuming you don't have Blitz you're going to be using Shiver to restrain the additional enemies lingering around and using Stagger to keep vana slowed somewhat. If you have Veiler you can also apply poison here. When you enter the mask phase you want to be have water ready, you have the lowest mask-dps so you re always on water duty and you need to do this properly; the single most dangerous part of the entirety of Darkfire Citadel is the mask phase if you mess-up watering. Ultimately, your main goal really is staying alive, keep your team safe and don't take dumb risks.

Fair enough, although it would be cheaper to invest in status UVs for armour than CTR UVs for bombs. Shock Max Demo set costs between 12-18kce, single CTR VH bombs usually go for at least 15k-20kce. Although if you don't care about going Max/Max, Merc Demo with Elite Bomb Charge Trinkets is a fair choice for Shock stratums.

You either seriously overestimate your own luck, or I don't think you're particuarly well informed of the actual chance of you getting specific UVs. If you were seriously planning to roll for these UVs yourself, I'm going to take this oppurtunity to suggest you don't, extraordinary luck aside if you want single Maxes per piece of gear it's often cheaper to buy them outright. Although if you're willing to settle for Meds or Highs you could get lucky with a few doubles, although even then any someone crafts with said UVs will likely be on the ah for less than the ticket cost adds up to anyway.

My prices are the market value of these items that players sell and buy for. There's no working out needed, I've been bartering for UV bombing gear for a long time now, and I've seen em come and go and bought and sold many above and below the usual prices. I've also rolled on stuff far more than I should and ragecrafted a lot of bombing stuff in the past, I'm telling you from experience that you're better off buying outright, or ragecrafting.

If you really want to roll or just spend a small amount of CE, run a mixed set. Mad + Volc/Merc mititgates the the status penalty somewhat and you can use trinkets to more or less get the same bonuses you could've running full Mad anyway.

And did you have any particular Sword/Autogun in mind? My only non-bomb weapons are my Lionheart Blade and my Volanic Pepperbox.

We must share high-fives and bombing runs sometime.

When I did Snarby, I used a Barbarous Thorn Blade, but that's mostly because I didn't have a Pepperbox at the time. It should serve you nicely.

For Unknown Passage, stick to Nitro/Irontech/BAB (whichever you may have), the Lionheart Blade for the part where you move through the maze, and your goddamn proto gun if you have to just for hitting switches. Equipment can be changed at any point during UP, but you won't really have the safety to do so.

I knew you were using Mad Bomber because I'm just that psychic. (Actually, it's just because you mentioned you were after the Mercurial Demo set, so I thought that it was most likely you were a bomber.)

Echoez' advice for the Shadow Lairs seems fairly sound, although depending on your team role you might want to select Electron Vortex over Nitronome. Also, the equip-changing doesn't really make sense logically, but given you can get every enemy type except Fiends in the Unknown Passage, you're going to want that advantage. And a Shivermist.

I don't know where the thing about swarm monsters being neutral came from, but the construct swarms are resistant to piercing and weak to elemental just like all other constructs. Lots of normal damage is popular due to the smegoff large lumbers, though.

They're also immune to weak freeze (shivermist). The bigger blast bomb you can bring there, the better.

Pretty sure that Swarm monsters have the standard damage inflictions, resistances and weaknesses of their standard versions. Only other notable features is that the Void Gels act as Toxigels with a spin attack and poison ability, Void Wolvers don't burrow, and Void Zombies are immune to Freeze (according to the wiki) and incapable of breath attacks. Nothing except the Gels actually proc for any status other than Stun.

"The usefulness of Mercurial Demo is debatable, since it gives up half the damage bonus of Bombastic in exchange for MSI Low, meaning you can't max damage and CTR without having VH UVs on every single one of your bombs. Its shock resistance is pretty useful, though."

Mercurial demo is really more LD oriented, where you'll have max CTR as recon anyway. Damage bonus is also better than CTR, only cause you can UV CTR and not damage.

"A 1 UV ticket costs 20k and a 2 UV one costs 75k."
They said kCE, not kCrowns. I think you doods didn't notice that, not sure.