1. You may be able to simply set the AP flat on top of a dresser or cabinet and not need to attach it to your ceiling. Included is a mounting kit for drop-down ceiling T bars, not drywall screws, etc.
2. Yes, PoE is needed as no AC power adapter is included.
3. Probably, depending on the building materials used (chicken wire/stucco walls can block RF),
but near a stairway between floors or in the center of your building will likely provide adequate
coverage. [but still needs to be tested to confirm]