You don't seem to be using Sepulcher Sentinel enough. Should be one of your first choices for Clan Boss, as well as your dungeon teams, except spider and FK. Lose Bellower in the CB team (what's he supposed to contribute there? Bellower is good against waves of enemies, what with all his AOE hits, not against single targets) and bring SS in. I'd probably recommend her as next 6*. Also, you could probably move on to normal CB already? 

For Fire Knight, remember that counterattack or reflect damage also count as hits against the shield. So your rares Fellhound and Grappler could both be useful there, what with their AOE reflect damage buffs. FK is a tough dungeon, especially on auto because the AI seems almost deliberately bad, but you could surely progress higher than 7 with your current level of progress. 

@L9753thanks for input. I guess ive been getting the wrong impression on Sepulcher ill try and use her in more encounters, as for healing what would be better between Vrask and Apothecary during mid game? i know apothecary is valuable in endgame.

okey gonna look into Fellhound and Grappler in FK and see if i can get some more progression there.

who would you recommend to replace bellower with on CB?

Sepulcher Sentinel instead of Bellower on CB. If she isn't performing so well, maybe check if her gear is right - in any case, she's a support champion, her job isn't to do big damage but to reduce damage on everyone else. 

Apothecary is important more for speeding up the team than for his healing - for pure healing, Vrask will do more, healing the entire team on every turn. I guess in your case you use Golden Reaper for speeding up the team instead, then maybe Apo isn't that important (he's also commonly used for his def aura in dungeons, but for that you have SS with a better def aura). 

You shouldn't have lifesteal gear on anyone except athel if at 

why is that? I have tried life steal on Trunda, Elhain, Kael and it works great and I was able to clear Campaign - Normal, Hard, Brutal so far

Bellower in a Stun set would be great for your Dragon team.