@Howard Handler, the art comes in finding the deals where the seller accepts $106k for whatever reason.

Under federal law there are only 2 questions any one can legally ask to any service dog handler.  1. 

Is there a platform that can pre-check prospective tenants and even handle rent payments, or is this getting into a full property management service?

It may have been her income that made it affordable.When one tenant wants to leave, it's important to verify the remaining tenant(s) can handle rent on their own.As others have said, once they bounce a check you should stop accepting checks from them, ever.

Make sure you can handle rent fluctuations, vacancies, repairs.

But either way you simply inform the handler that you will not be renting to section 8 any longer but may be stuck till their lease ends.

I also doubt any court would find you negligent as a property owner for any incident with a police dog under the control of the handler, and the handler is always controlling the animal, even if he leaves the dog inside and runs to the store. :) 

The air handler/coil is a 4 ton and the AC and heater are 3 1/2 ton. 

I performed an electronic leak search and found the air handler evaporator coil leaking.

The floor is glued down carpet and the hvac takes up a large back room cause the furnace and air handler is not on the roof.