This is an excellent mod! I love how much thought you've put into it. Some suggestions i have:
1. Since its gonna take a while to comprehensively script a zombie infection, it'd be cool to have some zombie infested cities. You could do this by having a zombie civilization with only zombie units available to them, and making it at constant war with other civs. This may or may not help, but using BarbarianCiv from Revolution mod might achieve the desired effect.
2. Make more than 1 kind of zombie unit. like other said before you could use the drown, also the Scaverous from FFH2. Also, it would be cool if you could make zombies pick up guns eventually Halo style. Or maybe zombie grenadiers.
3. Make survivors weaker than zombie units. They are a little weaker already, but for civilizations that are supposedly "in terror" of the zombies, the weakest units are pretty capable of taking them out. This would also force players to either research some military or create alot of survivors.
4. See if you can borrow the religious skinned cities from FfH. It would add some cool flavor to the game, and also demark the zombie cities if u decided to make them.
Culture is very confusing currently. It took me a long time before I researched beacons, yet some of my cities' borders would spread without having culture generated. I agree with the other posters idea of having a "broken radio" +1
early in the game that later becomes obsolete.
Either you just didn't get around to it, or i downloaded it wrong, but there are no effects for some of the civics, especially the dealing with undead ones. If you just need something to put there in the meantime, i have some suggestions:
Information Gathering: +
, maybe access to a national recon unit like the airship.
Destruction: +unit experience.
Worship: +
w/ religion, +
Enslavement: +
from improvements (mines, farms, plantations), +
Co-Existence: Can't enable peace with zombies w/o working on the python, so I'd just suggest +
, + cottage growth, + city growth, +
The idea of all the yucks is that living with walking corpses everywhere is gonna spread disease. could be useful for later infection models.