Vorpal bunny is easier if you leave one monster behind, from the first "batch" of wolves and marlboros. Then no skeletons appear.

If the skeletons do appear it is still easy because they are not immune to Phoenix Down. had Baltier with a gambit "foe undead / Phonenix Down" and they were killed on sight. I also had all my 3 guys doing "Drain" as a gambit so they didn't even neet to hit the darn bunny. It fell on 3-5 turns