I think that they should have NOPAIN, NOBLEED, NOEXERT and NOBREATHE thus they will be killable in head mainly and not in heart.
Also give them SPEED:1000.
Current zombies have SPEED:5000, these zombies are quite fast.
Also, give them Extravision.
I should also wonder, why do you have zombies with prefstring Tasty Brains? This would make other races like Zombies for their tasty brains.
I also suggest making them [CANNOT_UNDEAD]
Butcherable_nonstandard is a nonexistant tag now.
Don't make their venom snakeman venom. Make it Zombie Bite or something. It might be an idea, if you want them to be really dangeous, to give them a stunning bite that is EXTRACT_PERMANENT.
Pretty sure Reckless is no longer a tag. You'd have to check that though. Did the same as Likes Fighting.
Give them higher Layering, about 300-400, so they don't freeze to death.
Suggest that you remove BABY:1, and make CHILD:1
[ADVENTURE_TIER:1] - You may need to change the number on this, if you do want a zombie adventurer that is.
Make them Like every type of site. After all, zombies aren't picky.
Get rid of:
[USE_ANIMAL_PRODUCTS]
[COMMON_DOMESTIC_PACK]
[COMMON_DOMESTIC_PULL]
[COMMON_DOMESTIC_MOUNT]
[COMMON_DOMESTIC_PET]
[USE_MISC_PROCESSED_WOOD_PRODUCTS]
[UNDEAD_CANDIDATE]