Personally I hope the undead race has some kind of reversed interaction with bless/curse - debuffs (not damage) from bless, buffs or healing from curse.
Otherwise I think they're probably just going to have the disguise and hopefully not necessarily have the zombie condition (So you have to TAKE zombie to be healed by poison and hurt by regular healing.)
But I have nothing solid to go off of, since not all undead in-game have any set traits that I can tell.
