As a Shadow Defender, I am only concerned with armours that have the most Shadow Defence available, which is, of course, Dread Skelly. This armour, and this armour alone is therefore my area of expertise. That being said, the title states you can ask me anything and as such I shall answer your question to the best of my ability; even if the ability is severely limited outside of the range of Dread Skelly.

First of all, being a Shadow Defender, I am of course well-versed in the mechanics of Shadow Lairs. It is a myth that Shadow Lair armour sets are prohibitively expensive. In a general case, you split the cost of an SL key in four, making your share 450CE. At current CE prices this runs at about 33k crowns. Is this much more expensive than the price of, say, a Gran Faust recipe at the auction house? I think it is not. You don't have to buy recipes for Shadow Lair armours. Consider also that you can make both sets in one run. If you pay 10k for the extra material in order to do that, you've spent a total of 43k on the Shadow Lair run as opposed to buying recipes for a full Skolver set, which runs at 50k. You have saved money!

As long as one or two of your teammates know what they're doing and the rest are able to not screw things up, a Shadow Lair run can go without any problems at all. My first SL Snarby run had no energy revives at all.

If sword damage bonuses are relevant to you (as in you don't spend most of your time using Argent Peacemaker, Polaris or Blitz Needle for example, in which case you might find Shadowsun to be of interest), then Snarbolax armour is a fine choice for you. It offers more total status defence than comparable class armours and is the only medium sword bonus armour to offer shadow defence. The shadow med on your dusker set would also make your Snarbolax set have exactly as much shadow defence as Dread Skelly, more normal defence and just a bit less poison and freeze resistance. If you do not have any UVs on the Dread Skelly piece I would therefore have to tell you, *gasp*, to avoid Dread Skelly!

Fallen has normal and special defence comparable to Chaos. It also offers protection from Fire, which is of high value, and protection from Poison, which is useful both offensively and defensively. Having just one piece of it gives you penalties against fiend. However, a medium penalty against fiends is not all that bad. The damage loss at medium is very small and the most dangerous fiends have little health anyway. The damage medium from your Snarbolax piece would nullify it, anyway.

Crown of the Fallen + Snarbolax Coat. You end up with:
-A decent amount of normal defence.
-A respectable amount of shadow defence.
-Damage medium with swords against everything but fiends.
-Low attack speed increase for all weapons.
-Some freeze protection.
-A bit more fire protection.
-Lots of poison protection.
-Some negative curse that nobody cares about.

@Bopp
-Two on the helmet (The teeth are not horns, they're teeth.)
-Eight on each arm. (The claws are not horns, they're claws.)
-Two on each hand when you are throwing the horns because you are listening to epic death metal of doom.

Altogether 22. Their spiritual purpose is to be totally awesome and metal, inspiring confidence in your team because their most important member is donned in the remains of the demonic dead.

@Fehzor
I wear Dread Skelly everywhere, of course! My role in the team is to defend against shadow. When I encounter fire, shock or slimes, I will leave that to the team's Elemental Defender, Piercing Defender or Specialist.

A well-balanced group, of course, consists of a Shadow Defender, Elemental Defender, Piercing Defender and a Specialist.

Do not fight it, my brother! Once you are inside a zombie, you may wear it for optimal shadow defence.

I'm a fan of härdcöre bläkk dëäph mütäl of döôõóò0oøm, myself.

1. That's silly. Defence is of course the best defence. That's why it's defence!

2. Just one shadow defender for the whole party? Well, if the shadow defender is skilled enough, it should work out.

3. Shield with your skelly shield.

4. Of course not! I'm not Shadow Offender over here.

5. Shield with your skelly shield.

6. Shield with your skelly shield.

7. Shield with your skelly shield.

8. A force you need to defend against.

9. Shield with your skelly shield.

10. Five out of five.

@Aureate
There's always room in a party for a specialist. Just equip your Deadly Virulisk / Valkyrie / Dragon Scale set and bring along your Wild Hunting Blade, Heavy Deconstructor, Cautery Sword and Cold Iron Vanquisher. You are now extremely specialised!

@Unstable-Ordinance
Blood gets pumped from the heart, so that's where you go. Poke a drinking straw in there and it'll come out all on its own.

The Kat hats have all the freeze, shadow and normal defence of Dread Skelly, but there are three aspects of it that make it very much inferiour:

1. There is no poison resistance. When you're poisoned, your defence gets reduced. This includes the ever important shadow defence! What a terrible flaw for a shadow defender's armour.

2. There is negative shock and curse! Shadow enemies sometimes inflict those!

3. There are offensive bonuses on them. What on earth are they doing on my shadow defender hats? Get that out of here, I say!

No specialization? Clearly you're a cobalt knight!

A Heart of Ice where instead of freeze beasts and freeze fiends, you fight a mix of freeze fiends and poison fiends? Such a level doesn't exist so I don't really see the relevance.

Since you're just running through, defence is of utmost importance. Some people would undoubtedly tell you that you should get an Ancient Plate set and roll max shadow/freeze/poison on it. That's as defensive as it gets, now isn't it? However, if I may make an unorthodox suggestion, I think that perhaps you should just go with a full Dread Skelly set instead. Funny how it works out, but the armour just fits perfectly into your scenario!