The other consideration...are you exempt from the provision? 

It looks like I “may” still qualify for a partial exemption based on those 18 months. 

I've seen monthly stipends range from 1500-2800, specifically looking near the military bases, medical center, and airport. 

The original owner has a ton of exemptions so she only pays $400/ year on property taxes.

If you lived in the old house for 2 of the past 5 years you have no capital gains taxes if you sell within 5 years because it would be exempt.  

If you are raising money you will need to register the exemption with the SEC, and it will depend on whether you are using accredited or non accredited investors. 

I don't come from money and had credit card debt/medical debt when I started.

If you buy the property and live in one side for two years you would get the full primary residence exemption on that side. 

They have now stopped responding and corresponding to emails and the only phone numbers they provide go to a medical facility in Florida and a full VM box that never gets responded to.Am I just f'd out of my money here with no recourse or do I have any leg to stand on to try and sue them for poor due diligence and not fulfilling the promises made?

If you turn your primary home in to a rental, that exemption goes away.