I, personally, do not like undead in general and Liches in particular. The only reason I take on Devlin A. is because (without editing) a Lich is the only character in MM8 that can GM the elemtantal magics.I dunno aboout Simon. He can become quite powerful in mid-late game although a dragon replacement is not a bad choice either. 
I like Elsbeth early on because once she gets levitate, the party can go into Ironsand and lure those cyclops down to the lava lake shore, stand off (in the lake), and stick 'em full of arrows. Same thing with the Gorgons later in Ravage Roaming.
Loads and loads of XP.
