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

You can also send payments to credit card whenever you have spare money.

I could be misunderstanding how this deal was structured, but wouldn't the seller who is on the underlying mortgage have an incentive not to let it go into foreclosure since their credit is at stake?

So far mostly people are telling me I'm probably stuck until their lease is over. meanwhile I also need to pay down my debt and improve credit score. 

Congrats, on both of those deals and, more importantly, on staying persistent to find your niche.Lots of misinformation on this thread.Andrey is not pitching anything or lyingHe is not expecting 30% IRR on every opportunityFinding and vetting trustworthy sponsors is not as hard as non-syndication investors thinkPerforming diligence on sponsors takes years, not hours or daysMany sophisticated LPs perform extensive diligence on sponsors and opportunities that is not discussed on BP (TLO reports on history of crime, bankruptcies, collections, credit, businesses owned, personal residence owned, employment, family members (including phone numbers), even traffic violations...the list goes on)Many LPs leverage sites like Ian's, 506 group, in-person conferences, and one another to analyze opportunities and sponsors together (it's a lot more sophisticated that the "what do you think about XYZ" posts on BP)There are tons of sponsors and opportunities that don't use short-term, bridge financing or max leverageMost are using 5-12 year debt, with inception LTVs in the 70s and year 2-3 LTVs in the 60s (and carry high reserves on top of that)The opportunities discussed on BP are only a small fraction of what's available in the marketPrudent syndication investing is just like anything else in life...it takes diligence and time. 

@Geovanni Cano sellers don't like FHA, it is meant for people with little money and very low credit score, plus you have an FHA inspection which can derail a deal a week before closing, nothing the buyer can do.

Why set a 600 credit score if it's negotiable?

So act quickly, do as the others are saying and screen him according to your standard criteria. credit, references, eviction history, etc.

I have already been fully qualified for both the line of credit and DSCR.

Especially their Texas properties in falls forthworth area is under terrible management.