Well, I don't know about zombies. I don't think FWR would be satisfied if whomever he brought back was a zombie, that's not really "life." If you've read the seventh Harry Potter book, it's like the second brother in the tale of the three brothers, who brought back the woman he loved from death. But she wasn't really alive, so he wound up killing himself to join her on the other side. I would wager that FWR wants the real deal, not a sort of counterfeit like that.