@Richard Benjamin Wilhite, @Bill B.makes some good points about loan terms and the strict identification rules for a 1031 exchange.I would add from a tax mitigation perspective that buying the largest property possible will give you the greatest amount of cost segregation possibility and at the lowest cost since it would be one study rather than several. 

Heir, preforeclosure, foreclosure, divorce, absentee, rundown, can't keep up with maintenance, overdue taxes and liens, the list is endless.Don't try to force an offer on them, get to know them and keep following up.

I am not a tax expert, but here are my thoughts. 

The guest contacted me via our Zillow ad prior to the showing and was apprehensive.

You take all of it but make sure you put 25-30% of it away for taxes.

I’ve used seller financing as both a buyer and a seller and it can make a lot of sense in certain circumstances (for example I used it as a buyer when I reached the maximum number of conventional loans I could get, and I’ve used it as a seller to both increase my net proceeds (due to collecting interest as “the bank” in addition to the sales proceeds) and to lessen my capital gains tax hit by spreading it out over a few years).

I think the most important thing would be to have a strong contract in place and to have done thorough due diligence on the front end prior to signing up a contractor.

Quote from @V.G Jason: Organize taxes and eat better.  

It might be legal now, but it wasn't that long ago and they definitely have prior experience with these scenarios.

And if there is a "why" then the 1031 is what you want to use to get into a new property and defer all tax.