Lenders who understand and specialize in such properties can be more flexible with their criteria.One approach is to ensure you provide comprehensive documentation on the property's potential and zoning specifics.

I'm also pretty active on IG (@Househackandhustle) where I document my journey and try to create helpful freebies.

On investor products we would be maxed at 75% depending on the documentation type / fico score for the borrower. 

That language obviously isn't in the document.

We have been waiting for him to sign the addendum of the price update and provide some documents for the title all this time. 

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

All of which are well documented on the forums.

I care less about the payment process and more about communication, accounting, documentation, processes, etc.

All states and counties are different, so you need to read through the county documents carefully and consult a local real estate lawyer.Some counties will only sell the tax debt. 

Saying there are three people living there when only one is on the lease is good to know, but hard to prove; getting video documentation of three people consistently entering/exiting the property substantially alleviates that difficulty.During your due diligence process, you probably obtained a copy of the existing tenant's lease to review.