Through that lens I will try to answer your questions to the best of my ability:1.

They e-mail me their background check from the hospital, or I have them complete one through tenantbackgroundcheck.com. 

I can get traditional financing through a bank but was wondering if I go the "seller financed" route would that be more advantageous?

Some items might hold more weight than others, but you guys should sort through that together.You also might just do the partnership deal by deal - sometimes jumping into a partnership before you have officially worked together is NOT the best idea...

my condolences on your recent lost.there are a few ways you can do this, as mentioned above you can take a heloc on your primary residence which will give you a second mortgage, first mortgage payment wont be impacted. you can do cash out refinance which will give you one mortgage and payment. it will pay the old mortgage and give you money in your pocket to pay for the rehab.or you can do a renovation refinance which is similar to cash out refinance but we would contractor involved  as part of the refinancing and they are paid through the loan

I was a Platinum agent in NJ in 2024 so just trying to expand on that with lead flow but I am very skeptical of the lead generation through BP and have been for years frankly.

He uses poorly thought through methods, I've listened to his "methods",  Thus, he has the high amount of  Due On Sale called in a short period of time. 

I work with multiple different programs through our housing authority ("Section 8" and similar).

I think I went through 3 different people that were over my account because they would quit.

Since you're analytic savvy, run some high level amortization schedule scenarios to see how much equity you gain through annual principal payments.