I would change the zombie model (well, it's not right to put such monsters in a game and show them to people! just not right!! :mad: ) Only one cool thing is that the zombie is obviously a dead peasant :D Same massive belly, thick arms...
Also, I would remove the bone dragon (I don't understand the point of making undead dragons) and make the same-level undead 7th level — they look way too cool. For 6th, you could bring back the dead riders.