I'm glad to know you received your January payment.

that isn’t subject to higher down payment requirements or higher interest.

I was thinking I could put down the 50k so he had enough to pay off the heloc and make payments to him for the remainder to be paid off in 10 years with new renters.

I'm under contract for a nice double and was hoping to use part of the money for my portion of the down payment.

Quote from @Kevin Sobilo:Monthly Rent + Monthly Debt Payments <= Gross MONTHLY Rent * 45% Obviously I made a typo.

A line of credit won’t commit you to a monthly payment unless you use the money, so you can avoid paying interest when it’s not in use.

If the loan was fully funded at closing and since then the loan is in an interest-only payment period, these numbers would equal. 

But that also depends on your down payment- putting only around 20-25% down is hard to have a profitable STVR.Ultimately with STR v LTR, I'd be mainly curious about your intended use of the property. 

The current owner is letting me take over the property as a tenant as long as I pay the water bill and the mortgage payment on it and whenever I decide I can purchase property for the balance of the mortgage  they are in no hurry for me to purchase the home as long as the mortgage is paid. 

I do not have to do anything right now, I just need to learn, wait for the right opportunities, or create them - for example by trying to use subject to and take over someone else's payments who locked in a lower interest rate from a few years ago.