Would you ever want to return to the home? 

The net cost of the turns is what really matters to your return on investment.  

Getting a loan to payoff another loan with a lower interest rate doesn't make any sense. we do private lending and can get double digits returns consistently.

You can certainly find a property for cash flow that may also bring you a strong return on that investment.

Their numbers did not always add up from the initial calls to the follow up, and I believe the returns they are offering are super aggressive.

In the event your property does not sell, pivoting to a rental could be your best option and allow you to maximize return.

(if this makes no sense to you, research the 80's)Yes, fundamentals apply like compounding returns, proper use of leverage, appreciating assets etc etc, but the specific's of the how-to's, the "plays" one runs, how you play the game, it's a different game than '19'. 

Asking to anyone who has experience, knowledge or connections in these southern texas markets, how has this or does it affect your real estate strategy and returns? 

Another note on construction cost, going vertical is very expensive now and would require have a great connect with a developer and a builder in the area.See what rents are in the area and run the numbers to ensure the rents will cover your costs and give you a solid return—using the 1% rule can help.

Call cops if they keep returning.