Also, how should I present the offer to the seller considering that this isn't all cash?

You will earn a fee, learn, save then go on your own.

You may be confusing 'profit' with 'cash from the sale'.

If you refinance the rental house and get the equity out, you'll end up with a higher interest rate and a good amount of cash to use on your next house. 

Purchase price: $150,000 Cash invested: $100,000 Recently completed a purchase and renovation of a multi-family house in Cleveland Heights, Ohio (BRRRR Method).

They can pay that easily with cash on hand without even increasing dues.

It’s been unable to sell because the original house was a single wide in the 70s that was then added on to.This makes financing either difficult or very expensive for people (especially since it’s a low price point and mainly first time buyers).We would be paying cash - so it’s not an issue for us.

Between appreciation, loan buy down, and cash flow, you may exceed that $3,500 in cash flow. 

to do the cash out refi, for conventional loans like Fannie?

Save cash and look for a deal the second you turn 18.