I am located in Huntsville, Al and can confirm it is a hot market now.

Is there a way to confirm this stuff before I close on the deal?

You will likely have 50 numbers pop up to start calling.The quick and dirty way, to be confirmed by and engineer: look at the floor joists in the basement (assuming there is a basement).  

They will confirm W-2 income, DTI and other requirements.  

I'm not 100% sure though so make sure to confirm with an accountant.

You can look at your closing documents to confirm, but that's what the majority of lenders require. 

Anyone can confirm that I am on the right track?

And refuses to let me on the property to confirm and address the complaints and said he will not pay rent until everything is replaced.I offered $700 plus unused rent plus security deposit back and he still refused.

I was given direct contact information, but before I reach out, I'm trying to figure out the most important questions as an INVESTOR, to ask the potential seller in this off market situation. my initial thoughts are: 1) confirm their motivation for selling, 2) price they would consider selling 3) possibly seller financing options?

They want to confirm you are who you claim to be and that you have the authority to hire them to manage the property.Most property managers would not take these steps.