So I have been doing the witch/rogue combo. Ended up being a spear user with a half-n-half earth magic/witchcraft partner, no companions but yes to lone wolf.

Double pulled the two camps of undead to the NW of town (1 decapitator, 1 swordsman, 1 zombie from near the gate, then 2 archers, 2 swordsmen, 1 lieutenant, and 1 mage I believe from the broken house). Killed all of them and only lost probably 40 hp on my spear user, which had a lesser heal ticking up next turn to end the thing at full for both.

I know I'm not all that high level yet with this pair, but I'm supposing the problem isn't with class choice, but instead with personal familiarity with min-maxing and good environmental control, chokepointing, etc. I'll continue with the pair but from how smoothly it goes I'm not expecting a sudden change to "OH GOD IM DYING", since I didn't have that show up for my level 6's at any point.