That is the price of admission to borrowing.The majority of the US population is NOT getting paid under the table.  

That is a good price of admission to me.  

The MLS access and past sales data is worth the price of admission.

It's always best in these situations to make sure you create a 'paper trail' of the communications between you and the tenant, as it may be admissible to the court, depending on the your state's specific statutes and court rules, which I am unfamiliar with.This answer is not a substitute for professional legal advice and does not create an attorney-client relationship, nor is it a solicitation to offer legal advice.

The fact that Seller admitted he knew the hot tub needed to be replaced is his admission of trying to deceive you.  

By your own admission the inspector only inspected half the units. 

But you can't call admissions and ask them to confirm that he is or was a patient there.

@Aref Shehadeh  You could charge an admission fee.

Do REIA organizers typically charge admission for group meetings? 

Some of the items/infractions described are attributable to wear and tear and would not be admissible in court.Additionally, there is no proof that the crack in the refrigerator drawer cover didn't exist before you or ex-tenant were made aware of it prior to the cleaner's discovery.So, the bottom line is that you are riding a slippery slope and may want to come to some amicable agreement with the ex-tenant before it escalates.