There are regulationsI could go on, but if you learn this much, and apply it appropriately, you will cut down your sorrows and risk, considerably.And yes, there is much more.

It’s unnecessary and potentially problematic to add the ex-partner to the title before the sale.

For certain areas annual pest control may be needed for colder areas maybe you run the risk of freezing pipes.

In this instance what I would do is get the deed in lieu from the borrower so you ahve the property again and get a note from them but have an attorney draft it to see if you can include a confession of judgment - meaning if they do not pay then you can get a quick judgment and possibly garnish wages.I would also have them put a small down payment as part of the note and only accept a check that way if you ever did garnish you have a copy of a check so you know where they bank.unfortunately you are right they can stop paying on the note and its unsecured so its a risk but out of all the options this is your best option.

As the risk goes up the cost of money goes up.  

Potentially free parking for your guests.Condos can work too, but there are more variables out of your control.

You need to minimize upfront expenses because 100% of your investment is at risk and lost if the lot is not buildable.My favorite strategy is to locate the property and tie it up for usually no more than $100 for a period of 8-12 months, analyze it myself and if I believe it to have a chance at being buildable I create a permitting plan and market the property to other investors/builders willing to take on the permitting risk.  

Check AirDNA for demand, pricing, etc.The Dekalb Board of Commissioners has proposed regulations for short-term rentals. https://engagedekalb.dekalbcountyga.gov/airbnb-dekalb-countyShort term rentals require you or your property manager to be hands-on and come with more risk.

Because their investments do NOT have a higher enough ROI adjusted for risk.  

This just seems like it puts me in a potential bad situation if something goes wrong during the process.