Hi SupermarineXQ,You can have multiple sites in the same building, but keep in mind, in order to adopt Instant On equipment you'll need to be on that same local subnet / VLAN. After they're adopted you can make changes remotely.
You'll have to use a dedicated router for this, not an AP. You'll need to create VLANs and use a switch or multiple switches to distribute your feeds outward.
Remember, VLANs help to keep each service / collision domain separate, but VLANs alone aren't really secure.
How many individual tenants are you looking to serve?
Uh, umm, wait…..noooooooo.
You can't place a bunch of AP11Ds in a room and use them to break out individual subnets.
Again, you'll need a router capable of creating each subnet/VLAN. Then assign only that subnet to an individual port, and that port gets connected to an individual tenant. Or, if you're okay with having multiple tenants sharing the same VLAN, then a gang of those ports with the same VLAN, up to the tenants that will form this cohort.
Either way, the 11Ds are not designed to do what you're asking on this scale. You'll need a microtik or Ubiquiti router or if it were me, a PFsense appliance (or better). These will also be able to shape or rate-limit traffic as you'd like.