In both fights, you absolutely want turnmeter control. You should definetly open some green shards and level up Armiger to 60.

For Spider, it would be best if you do your tag team arena daily and buy Drexthar fragments in the Bazar as soon as they are aviable, to get this strong free legendary. Drexthar is a great spider bruner, especially at stage 20, where he has weak affinity and gets attacked by the Spiderlings. With mass hp burn on all Spiderlings, the fight is much easier. At stage 20, each burn deals 160k damage to the big Spider.

If you don't want to wait for Drexthar, you could try the following team: 

• Deacon (speed aura, decrease def, turnmeter)
• UDK (tank, to work as tank successfull in stage 20, your UDK needs roughly 300 res more than he right now to avoid the poisons)
• Coldheart (damage, definetly lvl 60)
• Armiger (tm decrease)
• Scyl (passive heal, revive, tm reduce and decrease speed on the A1, stun on A2). 

For FK, you could try 

• Deacon (aura, tm, decrease def), 
• Apo (triple hit A1, speed buff)
• Coldheart (4x hit A1, damage A3)
• Armiger
• UDK (to block the damage at the waves, otherwise your team may have problems to reach the boss)

For FK, the actual equip of your UDK is better than the suggested res equip for Spider. I think you should try FK first, and when that is done, do the Spider. Maybe you have Drexthar until then and can Replace UDK with Drex in the suggested team.

AoE HP burn is already covered by either Skraank or Achak. There are no chances Ill be able to build and gear both CH and Arminger by the time Ill sit on that mission, Drex is still 50 fragments away from me. So for now I believe my team will be something like:

1) Spider

a. Deacon for lead and TM control

b. UDK in high res

c. CH - obviously for DPS and TM control

d. Skraank - void HP burn and weaken debuff, self buff after each tickle of HP burn

e. Scyl - HP regen, stun, speed manipulation

2) FK

a. Deacon - as above

b. UDK - as above with current gear I guess

c. Apo - as you said

d. CH - as above

e. 

Last slot is still open, I guess Ill try different options. If I will face troubles to reach FK Ill try to use Vogoth (3 hitter, great passive for survival). If there wont be any troubles maybe some additional DPS or Urogrim for poisons. 

In conclusion I should focus on upgrading my CH fast as she will be foundation in both dungeons.

For Spider, especially Spider 20, I don't know if Scyl is going to be enough healing to keep UDK alive. I would probably go with Nia instead. She'll be able to keep him healed, and also provide a very helpful set of buffs. Also, although Skraank does damage, I don't think it's worth bringing along. CH can kill the boss. What you need is more TM control.

For FK, for that last spot you're going to need someone who can help with the waves, and, ideally, also help with TM control for the boss. CH alone won't be enough.

For both of those - how close are you to getting Visix? She'd fit perfectly - CC for the waves, and A1 TM control for the boss. 

I still need about one and a half month to get Visix. For TM control maybe Nethrill? He has some usefull TM manipulation with AoE stun for waves.

So I have tried on auto the spider 20 with CH being 5 star, UDK in regen gear meant for different content and w/o any res. I would say... close enough. CH will make this team to work.

i