Some of these other options you listed are decisions based on how you want to live and how you feel about having strangers in your primary house and aren't something we can tell you to do. 

You'll have the option to refinance later when rates decrease, if necessary.

Would you consider MTR and STR as back up options?

Would you suggest hiring a company like Healthtrust to do the feasibility research for us or is there a less expensive option?

The better option is for the Seller to pay your closing costs.

Once you add up the lost rents, damages, and increased liabilities this tenant brings you're better off starting proceedings now.Another option?

I would change my tone with the old contractor and notice him in writing he's not welcome back to the property and you are looking into option to hold him accountable.

That seems to really restrict the buyer's options and avenues for closing.

I would recommend reaching out to a few to get a better handle of your options.

@Juan Lizarazo plenty of options around.