Sorry, they lose health, and fall off of it when they are killed.

First of all, I would like to commend you on your excellent work and dedication; I can imagine the challenges involved in this project. I believe this set would be extremely valuable for representing the Aztec civilization in a future mod set in the Middle Ages or the Early Modern period. However, I do not think it is suitable for the Zapotecs and Mayans, as they are distinct peoples with completely different languages. Given the available Zapotec material and the need to avoid Hispanic influences, I do not consider using Nahuatl to be the best approach for them. I recall seeing some Zapotec dictionary projects; with a little help, perhaps we could get something close enough to be decent? The same approach would work for Mayan languages—which might actually be easier, given the more comprehensive linguistic studies available.

You mean that, if they are shot, they don't lose health, but they fall from up there?

Garrisoning hides the unit inside of the building, spitting them out when it is destroyed. They also add to the building’s default arrow count. Turreting places the unit on top of the building, kicking them off when it’s destroyed, and also allowing them to be shot off of it. They don’t add to the default arrow count (if there is one), but since only archers, slingers, and javelineers (and Crossbowman) can be placed on top, they can fire on their own.

I'm sorry, but this makes absolutely no sense. Nahuatl appeared centuries after the time frame of Empires Ascendant. The Maya didn't speak Nahuatl. They didn't even speak languages that are part of the broader Uto-Aztecan language family.