I’m going to sell this property soon as my HOA won’t allow me to transfer it over to an LLC.We want to purchase 5-15 doors (2-6 multi family homes) in the next twelve months and I currently have about $5000 saved and potentially have access to an additional $150k in family/friends money.

It’s a double lot (6400 square feet) that had a 700 Square foot addition added around 1940.

There is also a possibility to purchase additional acres for building. 

A roll-away center island might help with storage and give additional working counter space.

I agree with those who hinted that you'd be wasting your money if you put your own money into accelerating your mortgage payoff, when those same dollars should be going towards additional investing.I'll repeat Joe's point: don't help your tenants pay for the properties you already "own"!

I would love to help you with the bigger projects only (additions and larger).

In addition, I would recommend: Listening to the BP Real Estate podcast https://www.biggerpockets.com/podcastListening to the BP money podcast https://www.biggerpockets.com/moneyshowAttend your local REIA meetings to networkStart analyzing deals to get practiceEngage more on the BP forumsAll the best!

The question is whether or not the benefit of getting the third property without any additional cash out of pocket is worth increasing our debt. 

In addition, attend REIA meetings and study.

Even if you engage a broker, you should still shop around an additional couple lenders yourself (if you have the time/energy).Freddie SBL loans cap at 50 units, so you won't be able to take advantage of that program (unless they can somehow make an exception), but there are still great Agency (Fannie/Freddie) programs that would work.