They are often shocked to hear from the most successful and wealthiest people in America that failing often is part of the process.People's state of mind shows how they react to adversity.

Did some down right dirty adverse posession stuff.

I live in the San Francisco Bay Area and although I have rentals here in the Bay Area my next purchase will be in the Midwest .... most likely in the next couple of months.Through much Persistence I've been able to find agents and property managers in 2 markets that  considering and will be flying to both places next month before making a decision on which one.I used to be completely adverse to investing out of state because I wanted to be able to drive to my rentals and be able to "check in on them" with my own eyes.....until I started listening to the podcasts of people on bp here and how they did it as well as why (cheaper to buy and better cash flow).

So I don't know how the slab would adversely affect anything.

A broker/agent with NO INTEGRITY will put their needs FIRST ahead of protecting a client and tell them anything to get that commission check and make a deal happen.That is NOT the way to run a long term business with credibility.How you make sure you are not liable it to DISCLOSE EVERYTHING you know and sell AS-IS.Fill out the sellers disclosure in full truthfully and honestly.AS-IS does not mean you are not disclosing known material facts as a seller.It simply means you are not going to fix them and it's up to the buyer to investigate further.By the way even if you do everything right and disclose the buyer can still sue you later.Buyers can sue for anything but it doesn't mean they will win but just sue you fishing for money once they realize they made a mistake.Usually the judge hearing the lawsuit will see that you fully disclosed and the buyer did not want to spend more money doing the proper inspections before closing.The judge will then dismiss the case usually because the buyer did not perform fully "their right to their own inquiry" before closing on the property.Where you get into trouble is the question you are asking now about I know something and fixed it but my agents says I don't have to disclose it.I can tell you that is absolutely wrong.Fixing a foundation crack and changing a rooms use known for water intrusion is an adverse material fact that you MUST disclose.Many sellers do not want to disclose items because they now it will reduce the sales price.The seller will pay for it now with a lower price or pay later with a settled lawsuit with claims much larger than the lower selling price.The seller usually buying a lemon house themselves try to pass problems off the unsuspecting or not knowing buyers.You as a seller just have to learn from this experience and make sure what you buy going forward is thoroughly inspected.No legal advice.

Will the non-recourse (no personal guaranty) debt from the other 2 properties adversely affect my DTIR for this refinance?

If you are risk adverse real estate, (especially out of state) is not for you.

Impressive story, I am sure you and your family are stronger after all the adversity you were faced with.Good luck and happy investing Derrick

“Every adversity, every failure, every heartache carries with it the seed of an equal or greater benefit.” 

that's the question.Also, google "adverse possession."