Hi,

CB: Coffin Smasher, Aothar, Bulwark, Sandlashed Survivor and Apo

Arena: High Khatun, Seeker, Warmaiden and Kael 

I agree with Valdys suggestion.

For dungeons progress. If MM stands for miscreated monster he and apothecary will rock your world. Almost any other champions and you are good to farm dragon.

I would ofcourse highly recommend royal guard who is excellent in both dragon and spider. With these three champions you have long-term solutions.

You dragon team all the way to dragon20 could be:

miscreated monster (Primary role: keep your team alive. He brings stuns, ally protection and some shields)

Apothecary (Primary role: speed booster, secondary healing).

Warmaiden (Primary role: decrease defense)

Royal guard (Primary role: nuker, does bring some turn-meter reduction along the way).

Kael (primary role: nuker, poisons are good on boss aswell) 

For Ice Golem, Dark Elhain should be useful because of her passives, as well as anybody with block revive to keep the two minions down. Queen Eva has a block revive but on long cooldown, while Fenax has one on his A1 which in my experience tends to ensure even on auto that at least one of the two stays down, with some luck both.