;) Make sure to find one without monthly membership commitments, flexible pricing, and an awesome affiliate referral program! 

I'm with @Cameron Tope, NARPM affiliates are, by in large, higher quality PMs. 

Some credit unions pool their loans only to credit union affiliates and you might not know it's sold as the bill still has their name.

I'm not affiliated with them, but they did good work, relatively fast for a good price.

The difference is that instead of a lender and borrower, the scenario is a vendor that helps schools, churches, and other NPOs fundraise, and an organization: agent refers NPO to agent who is affiliated with vendor, vendor offers referral fee to agent, agent splits referral fee to agent that referred the nonprofit.Is there anything--legally or ethically--that would prevent agents from doing these, or can it be done, without any issues?

I used it for a 30K rehab, cash was fast and the interest rate was reasonable. those are 2 options you could consider (I don't work for or have any affiliation SunTrust bank, simply a happy consumer)

There are many other options with flexible pricing options and affiliate programs (which end up paying for batch skip tracing).

I am working with Zach from RTR as an affiliate and know he puts a lot of emphasis on analyzing exactly those relationships.

It ranges all the way down to affiliates who are really commissioned salespeople and have no responsibility whatsoever. 

I tried selling on Amazon, day trading, affiliate marketing, dog walking, and T-shirt printing just to name a few.