Fahrakin, UDK, Occult Brawler, Scyl, Ninja, Deliana should be a good start. I know it's 6, you will have to alternate based on affinity. I'd assume Kael, Vergis, and Miscreated Monster are also good for early CB. 

I'm sure someone will be along shortly to give a more detailed breakdown. 

Hi there, and welcome to the forum.

I'd avoid Scyl in CB just because the passive is annoying due to not choosing where the speed boost goes. Absolute pain for tuning purposes.

The four I definitely want:

Sepulcher: Defense up, attack down, block debuffs so now we're affinity friendly and can tank the stun

UDK: backup attack down, damage mitigation from the shield/passive, continous heals

Ninja: one of the very best DPS in CB, not much to say there, will help with defense down on a1

Fahrakin: more dec defense, DPS from A2 + the best non legendary ally attacker in the game

It would be nice to have some other damage mitigation/healing champs, but in lieu of those I think I'm fine going with Kael for now as the fifth. 

I'd probably want to go for a 4:3 tune with Sepulcher and Fatman. If Ninja plays nicely with that tune, then great, we use him, if not, we drop him I think, I guess for OB. Deliana in for Leech (turn off A2 and A3). Maybe Miscreated for the AP on turn 1?

Make your Ninja lvl 60. No lvl 50 champs in CB. The base stats are low and you can't get Warmaster/Giantslayer mastery before your champs are 6*. The masterie alone will do millions of damage from all 5 champs.

You want the following debuffs at CB (debuffs you have with my suggested team): decrease attack, decrease def, weaken, poison, hp-burn, leech (the latter has to do with Warmaster/Giantslayer, the damage from these masteries can leech. Much more healing the small amount Scyl provides).

You want the following buffs: Increase def, shield, ally protection, heal, strenghten, block debuffs

Sepulcher: decrease atk, increase def, block debuffs (2 turns on a 4 turn cooldown, I don't know if this will block the stun all the time)

Ninja: decrease def, hp-burn

Deliana: leech (disable A2 and A3). You may remove her when you get a better source for leech later on, she can shine better in other parts of the game than CB

Occult Brawler: one of the best CB-poisoners in the game, much better source of poison than Kael

UDK: Aura, backup decrease attack if Sepulcher fails, heal, shields

Not perfect, but you have to work with the champs you have.

Thank you guys so much for the fast response! I got a good pointer of of this, cheers!