The doctor found out that I was going to visit those 10 to speak in person with the borrowers and try to decide on the best course of action.  

Personally I’d have them start saving up and get traditional financing and pay you off.

Put an enclosure around it, heat it when necessary and  call it an indoor pool.My next personal house is just going to have a smaller pool like one of these.

STRs that I could use for personal use (family vacations) once or twice a year.  

Also, bear in mind that I have no idea about your personal situations and objectives and I don't like giving cookie-cutter advice to people.

Look for something that is going to support your lifestyle aka will give you points in categories where you spend AND reward you with points that are useful to you.Hope this helps, let me know if I can clarify at all

That person already had that money spent in their head even before the property is sold

There is of course a higher amount of money that is being invested, but as they say, high risk, high reward.”Please let me know on your opinions! 

It's high risk potentially not so high reward situation. 

Personally if it is a loser for 2 years, then it is a bad deal.