Hello XanaviNismoNurb, welcome to the .Org!

AFAIK units are indeed limited to one special ability per unit, and adding new special abilities goes a bit beyond what modding can achieve.

For your other questions, check out the Scriptorium: https://forums.totalwar.org/vb/forum...77-Scriptorium

If you cannot find the answer there, you're probably better off asking over at the Total War Center, as unfortunately our modding fora are rarely visited these days: https://www.twcenter.net/forums/foru...d-Mod-Workshop