This may need to be taken with a grain of salt, but I have looked each up on Trustpilot and included the scores below.

They can also be great for situations where you are looking to secure a property with more conventional financing, but don't have enough time to close with the original financing.

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

Originally had an order in for 3x 8' culverts that would be roughly $547 each because no one had them in stock.

The original basis carries over up to 300k.

5+ units DSCR or commercial mortgages. each one is used for different things. really matters purchase price. location of property and your physical location. dscr looks at the property and your credit score. commercial bank looks at you and the property. tax returns, w2s DTI. then the property needs to cash flow enough for them. dscr is a bit more lax but higher rate.

@Michael K Gallagher We originally planned to build three houses on the lots (1/3 -1/2 of a block).

As a joint owner, only her share would receive a step-up, and you'd still owe capital gains tax on your portion based on the original purchase price. 

Ran across FasterFunds lending where they defer paying origination fees upfront and make it payable as part of the payoff.

I recall seeing a recent post from someone else in a situation like this, he even paid the collection but score is still too low to apply for a mortgage.Certainly speak to an attorney to double check your options.