Well the Tlatchli isn't that bad compared to the Tsikhe.
You need amenities going to war all the time anyway and they look for amenity sources so it fits them.
Anyway a Library replacement I think either one or great writing slots would work for the building whether it be Babylon or Assyria. For Babylon it could be called a Tablet House.
If it would be for Assyria I think it could provide production for units in the city until the slots are filled.
I learned that the Assyrians built some of the first armories/arsenals in the world and I figured that would also be a good unique infrastructure as well, though maybe an earlier armory building would be OP. Then again Gran Colombia needs a counter.