Is it even possible to do or would they have to sign a whole new document?

They want widened door ways and God knows what else after that. 

My townhouse is all-electric with no garage, no fireplace, and no bbq grill, so no source of carbon monoxide.

Most court house buyers like me would never have even talk to the owner would have just went straight to eviction and ended up with a mess.. my style was to always knock on the door and talk to the person who lost the house.

Layout reminds me of small time share condos but the other condo complex next door does not resemble this one at all.

Detached Garage: 1800 SF, brick.

And you have to live in the same unit as the guest, bedroom doors cannot have outside locks, and you can host at most 2 guests at a time.

If the tenant is not allowing access to do a repair (NEVER in 10 years has this happened to me) you put a 24 notice on the door and go in.

It seems to me that rather than 54 doors, you/sis/dad would be better off with fewer, but better doors.

Turning a garage into a game room will probably pay for itself relatively quick.