Ok so this is a late post, but I've been very busy so it's amazing that I've got this in. Now my civ will be similar to the vanilla Aztecs and some of the other proposed Aztecs from this site. But like I said I didn't have a lot of time and this was and easy(ish) nation to do. So I present to you
Montezuma of the Aztec Triple Alliance!
(Also one, sorry for the long descriptions. I found no better way to explain the uniques or how to incorporate them into the game with what little information I had, two since I couldn't decide which building I wanted, I've decided to add them in as 3rd and 4th UC. Cause there's no rule against that.)
The Aztec Triple Alliance under Tlatoani Montezuma of Tenochtitlan
UA: Flower Wars
May annex City States with

faith by being at war for 5 turns or more and eliminating half of that City State's military. Alternatively, may puppet City States with

Faith by demanding tribute. +15% Combat Strength for units outside friendly territory.
UU: Quauhpilli (Swordsman replacement)
The Quauhpilli is a unique Swordsman replacement for the Aztecs. Receive +33%

combat bonus when fighting in forest or jungle tiles and doesn't require iron. You can also sacrifice one

pop from a city to instantly recruit a Quaupilli.
UB: Telpochcalli (Library replacement)
The Telochcalli is a unique library replacement for the Aztecs. Instead of giving it usual bonus of +1

Science for every 2

Citizens in the city, the Telochcalli give's +1

Science and

Faith for every 2

Citizens in a city while also costing 50

Production instead of 75

Production.
The next two uniques are the 3rd and 4th UC's.
UB: Calmecac (University replacement)
The Calmecac is a unique University replacement for the Aztecs. Instead of it's usual bonuses the Calmecac yields +33%

Science (+50% with Free Thought policy) and +33%

Faith, +2

Science and

production from jungle tiles. Has the two

Science Specialist slots plus a

Priest and

Engineer (renamed Artisan) specialist slot. (The Priest gives +3

faith and +3

great person points towards Great Prophets.) Doesn't require a library to build.
UB: Double Aqueduct (Aqueduct replacement)
The Double Aqueduct is a unique Aqueduct replacement for the Aztecs. Along with it's usual benefits, which is +40% of

Food is carried over after a new

Citizen is born, if a city is

connected to the capital and both the capital and that city have a Double Aqueduct, then the Double Aqueduct yields +5% more

food and all tiles next to fresh watter yield +1

food.