The litigant attorney only learned the owner moved to Florida after selling the business and bought a home there.

Lessons learned?

Say fair market value today is $250k, and a person doing DSCR will be around let's say 8% all said and done.

What I am trying to do is construct the home while learning from my father-in law who has been a licensed home builder for over 30 years. 

I learned a good amount managing my own Airbnbs across different markets, and did a great job doing so, that gave me the idea to offer my services to other STR owners.

Unless I'm missing something here, it sounds like just renting it out personally is the best option. 

I personally don't agree with the cost per square foot method, way to vague and inaccurate.

The study identifies with forensic engineering detail the immediate Bonus Depreciation 5, 7 and 15-year personal property class lives qualifying portions of a building that are normally buried in 27.5 year residential or 39 year commercial categories.The Cost Segregation Study was performed on the Asset Depreciation Range (ADR) and is based on a 40% tax bracket for State and Federal Taxes.

For example the person moves out Sept 30th, new tenant moves in October 1st.  

They're more focused on the property values than your personal finances.Explore crowdfunding platforms as an alternative to traditional bank financing.