The seller needs moving money, there are oftentimes an arrears that has to be paid on the loan, there are oftentimes HOA fees that are due, there are title costs, there are escrow costs, usually there is deferred maintenance, you have to make mortgage payments out of pocket until you get a renter in there, you have to pay utilities and taxes, and you need reserves in case it all doesn't go as planned.3.

I have family in Fl and grew up there.I have enough saved for a down payment, FHA or conventional up to 50k.

IM USING HARD MONEY SO THOSE MONTHLY INTREST ONLY PAYMENTS ARE KILLING ME ASWELL 

I wanted to get into a quadplex but came to a realization that it was too far fetch for me when my lender ask I need to have 70K total (down payment/closing & 6 months reserve) for a 535k quad.

It gives you the highest possible mortgage payment. 

The best solution in your situation would be to get a non-owner occupied loan with no pre-payment penalties to buy the building then cashout refi in September when you move. 

@Alex ValenzuelaFocus on loan term if they don’t negotiateAmortize it over 30 years and your payment will be peanuts.

Should I at least offer to pay the down payment?

The most important thing to consider would be that if you're using your HELOC for down payment / renovation costs and holding costs, then the refinance MUST get you all of your cash back to pay the HELOC back to 0.

I often joke that if they want a 1/3 of the revenue they should put up a 1/3 of the down payment and co-sign for the mortgage..lol Also depending on the geographical region, there's a chance the larger PM operations could be managing several properties in your area.