Yeah thats what i did...keep at least one person a zombie at all times (preferably the one with the highest hp) Make sure you dont use spells that cure the whole party....because then you will damage the one with the zombie status. Use items or weaker healing spells that only cast on one meber of your party at a time.

I didnt know any cheats....but the way i got loads of items was by collecting all the fiends for the man in the cave.