On the flip side, if you've got a bunch of Section 8 tenants living in a building that's in a neighborhood where a lot of the tenant base has good jobs, high credit scores, and are generally reliable people, you've got the most risky tenants in that tenant base and that ain't what ya want.

Specifically, I am looking at partnering with an individual who owns securities (stock and mutual funds) having them take out a line of credit against their portfolio (SBLOC) at a low interest rate, and using that to purchase properties rather than using a mortgage.

If you have casued damages since move in please let me know which those are and I will get you a quote.

Your name and credit would stay with the existing note, which you would keep paying on - ideally yourself with money you receive from the "buyer", because if they don't pay your credit is wrecked and your house is in foreclosure.If you search on here you'll see everyone and their brother looking to do Subto and it's a nightmare unless the buyer has the funds to pay the note off if/when the original lender figures out you don't occupy the property any more and are attempting to do what you want to do, since most loans are going to specify that performance.  

But somebody could use a credit card fund the immediate need and then pay it back with the policy loan fairly quickly.

DSCR loans are based off of down payment, credit score and either actual or market rents so it helps to supercharge an investor's real estate goals and net worth.

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

There are also 'mezz' lenders (typically for larger transactions) who will cover up to 90% CLTV and require you to bring the remaining equity to the deal, and additionally there is Gap Funding in the form of unsecured personal debt.The latter can potentially be the most expensive option, but allows for true 100% financing as there are no restrictions for how to use these funds, as they are unsecured, and generally obtained through personal credit, income etc (since there is no collateral for obtaining these funds).

I don't take credit cards but I believe stripe does.   

If you are looking at FHA because of credit score, then I would work on credit scores to qualify for conventional financing or see if you can get a very strong coborrower with high scores.