My thinking immediately turned to researching local rental costs per square foot to determine income potential with triple the current square footage.

It appears these investors merely provided unsecured loans to RAD who in turn purportedly made loans, although its unclear if that ever happened.

What are the largest pitfalls one may run into that turn this from a 150 to 350 ordeal?

Does anyone have any experience with using an FHA 203k Loan on a multi and turning it into a house hack in Massachusetts? 

I turned the two smaller bathrooms in one of the apartments into larger one.

And what is your price point and are you looking for turn-key properties or something along the lines of a "fixer upper"?

At that time we could renovate the ground floor apartment and potentially turn it into (2) apartments for a total of (5).My questions come down to how do we deal with the existing 40k mortgage, whether we can make it work so her parents aren't paying much in rent, if anything at all, and whether or not we set up any legal entity, like a trust to help the legal situation of paying off her sister down the road. 

I buy to rehab and turn into rentals so Pinson, Pelham, Bessemer are a great fit for the areas and returns I'm looking for.

My Expensive Lesson)My first rental with REI Nation turned into an absolute money pit.

Quote from @Devin James: Im currently learning this lesson with New Builds that have taken twice as long to complete than anticipated.....Finishing a Real Estate project ASAP is critical because...1) Holding Costs add up quickly- Loan Interest- Property Taxes- Insurance2) Investor Capital- Our financial projections are dependent on how fast we can turn our investors capital.