I was unwilling to simply loan him the money to satisfy the mortgage company (because he clearly doesn't pay his debts!)

The tennant has shown they are either unable to afford the unit, or unwilling to follow the rules (lease) and are testing the boundaries of what the PM will allow.

If the sellers are unwilling to put in the work required or are unable to gain an advantage against the bank then both they and you will be at the mercy of the bank and you will end up frustrated and empty handed.

Any realtor who is unwilling to do this doesn't deserve your business. 

This one will only big you down.Go look for opportunities where you can solve problems that others either cannot or are unwilling to solve.

Unfortunately he's unwilling to cooperate.

I see so many millionaires made on this platform, but many who have real estate portfolios that don't actually generate cash flow, and 401(k) balances that they are unable/unwilling to spend.

If he is unwilling, then you can start foreclosure proceedings for breach of contract on his original note.  

If he is unwilling to leave, regardless of what was signed, you have to file for an eviction and that is costly and onerous especially at this time. 

Most people here are unwilling to share exact wealth numbers, myself included.