>>when manipulating undead, can they hit one another or do they constantly miss?

Undead and cursed critters always go after the empath rather than doing the protect my friend routine like goblins do. There's no maintenance cost, but everything else is the same (the undead/cursed critter won't do anything if you fail to turn the critter, you still pay the initial concentration cost, and there's no skill modifier strictly for attempting an undead/cursed critter.)

You also have to remember that undead are a bit beefier than turnable critters in at least some of the stats/skills that go into the manipulation check, so they will be harder in those regards.

J'Lo, I'm a ranger.. I'd believe anything.....
The Manipulation List -- http://symphaena.com/index.html