A crucial element you don't describe is the construction.
Most high-rise buildings have interior walls of very heavy
materials, because they are part of the support structure.
If so, use an access point in every unit--don't try to service
a unit through a concrete wall.
If you do that, the UAP-AC-Lite is probably sufficient, and
is the lowest-cost radio in the lineup. Also, because each
unit has its own cable, you can power it via PoE from a
central switch.
Yes: you'll need to segment the users; a total of 216 units
with likely 2 to 5 times that many users is a serious load! Dave