It's basically a converted motel so each unit has a kitchen/dining room, a hall with bathroom, and a living/sleeping room with a walk-in closet.

As you have seen already...They somehow manage to force them, cajole them, bend them, cut them, poke them, rip them, etc.......I have seen everything from cutting them open purposely (to get in an open window on a lock out), to a full on Houdini cat claw jail break escape; then there is the just plain crushed like an accordion and shoved in a closet with no explanation...

Some of my tenants bring portable ones.I wouldn't want to be without a dishwasher, but recently on a trip we stayed with family who didn't have one.  

The morning after she turned over the keys she asked if they could come back to get some crib pieces that had been left in the upstairs closet.

The garage is already sealed off and has a heating and cooling vent inside the room, but no window or closet.

(Hint: a locked closet door with light shining under the door- could be a pot farm!)

Best thing to do is pay a little more than a window unit and buy a portable A/C & Heating unit on wheels that you can roll around and put in your rentals temporality when A/C goes out that you can have an use for the next 20 yrs.

I have installed one or more water closets not exceeding 1.6 gallons per flush.

Bring in window units or portables?

I am a closet introvert.