They would not be recording a lien or anything, just giving me the funds to purchase cash.

But the length of your loan will eventually shorten if you add to it.Start a money market fund account with Schwab or Vanguard and save at 5 or 6%.

He brought 100% of the funds for this deal.

You need to maintain a fund to handle those unforeseen expenses

Quote from @Cynthia Lee: Accepting even $1 could be seen as evidence of a payment plan, and the entire eviction process could be derailed.Once you start the eviction process, to not accept any payment unless it is a full payment in certified funds (cash, money order, cashiers check).

Real estate isn't the same as buying an index fund where you buy it and forget about it for years. 

But that wasn’t what the funds were for, they were origination fees - not prepayment for his time to go find a lender.

I am starting to look at funding my next deal.  

Yes I do indeed have other buyers that fund deals with me (is that what you meant as connections?)

Otherwise, a PMC needs owner input & funding as things happen.