As far as bank is concerned, I am still the borrower, because we did this transfer behind the bank's back. 

Mainland banks can not finance in PR. 

The thing I'll be changing is the financing I've been doing with a local bank, which has been a bit slow and cumbersome.

I have also run the scenario of putting extra principle payments into the conventional mortgage, but we cannot put away as much, because we have to bank for large purchases down the road.This spreadsheet takes into account that my wife takes a drop in income in the next few years to care for babies (growing family), also factors in major expenses on the rental property, and assumes that we have 10% rate on the HELOC to be conservative. 

I would be happy to take 20 percent down, and owner finance each unit, if banks are that picky. 

We neeed licensing for wholesalers as well as the banking and mortgage industry to start calling more notes due.

I'm looking for the cleanest & most visible way to access payment history, see amortization schedule, tax documents, etc- much like bank softwares provide. 

Run credit and background checks, actually call the listed referrals, and ask for bank statements.

Commercial loans are usually held on the books of the originating bank.

Quote from @Samuel Coronado: Quote from @Jordan Moorhead: You can use local banks and there are national lenders.