My strategy (for the Necropolis one:

Angel Eddie : Banner/Sustaining
Necropoilis: Strike/Advantage/Cosmic for HP (so.. random talismans :P )
Dracula: Reaper/Sacred
Magus Maya: Singularity

Basically, dracula puts crave on all enemies. (and Necropolis enemy cures everyone when he dies)
What I do, is try to kill Necropolis first (one hit of dracula, is usually enough) and then when he revives, put crave on both and kill him again, then both die together. If I happen to kill them both on the first round, then when Necropolis dies the second time, revives the witchDoctor, but with patience (because Labyrinth ) but he doesn't really hurt my team at all, and gets eventually killed