Looks good to me!
Sounds good on the Int.I agree with Freyar about intelligence, and since they're intelligent, they should be able to keep class abilities and hit dice.
Good point. It was clearly intended for humans and demihumans, which don't make for a wide variety of zombies.Maybe we should do this as a standard monster. It's pointless to make it a template if they're not going to retain class abilities, and I can't really see this work for non-humanoids.
Good point. According to the conversion book, 18/50 is the upper end of 19. Want to go with that or with 20?The strength should be a lot higher than 12; the original description said it was 18/50.