I'm fighting last battle in Chapter 1. My henchmens are Sharwyn, Deekin, Natthyra (sp.?) and I'm bard/rogue (mostly bard, though). I strip some of Sharwyn equipment, because I'm afraid I will lost some of it, but not all. I didn't remove anything from Deekin. I sold some of stuff, but kept Armor of speed, Gragoyle boots (I need to use it, maybe it will help), bastard sword I can use, gems, harps, etc...
My tactic was to ignore all the drows and just bash the stones and use bard song. Proved to be unsuccessful, Sharwyn is first to die, Natthyra stands in the back, Deeking is alive and well, no harm done (I don't know what he does), but I got poisons and ability damage quite fast. And die.
I guess I know what must I do, but do you have something to add?