@Erich HatchFirst, I look at permit history.

You only need a place to track tenant information, payment history, maintenance, etc.

Their job history tells me a lot.

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

At least prepare solid rent history showing how much you collected and if it was paid on time. 

Factors you should be looking for are: Job growth, population growth, low unemployment rates, increasing demand for housing, housing price history, and rent cost history.

You only need a place to track tenant information, payment history, maintenance, etc.

This eliminates the requirement for a new down payment since you are refinancing the existing debt.Lenders typically require:A copy of the owner-financing agreement.Proof of on-time payments (6–12 months).What to Do:Find lenders that offer rate-and-term refinancing for owner-financed properties (portfolio lenders and DSCR lenders often do this).Maintain a clean payment history.” 

It was sitting on the market for a few months so I offered well below listing price and the rest is history!

currently using avail for taking payment and applications ( including backgrounds, eviction, rental history, history,etc); also allows for lease generation.