I am not well versed with this section of the tax code, but advise caution and due diligence if you decide to proceed with your strategy.The BRRR strategy is designed for rental properties.   

And partnering with people who have done it gives you a fast track to the know-how vs a trial by error approach. 

Is there a different approach that anyone is aware or has done? 

Those "Fannie Mae" guidelines are the "allowables" set by Fannie, and only mean what Fannie will reimburse the servicer for, not what the actual normal costs are and even then, it's only when the servicer is using that designated counsel approved by Fannie.

Around here about $90 to $100 a square depending on finishes and complexity of design, which would include driveway, septic system, and no landscaping

If you're buying it cash, different story.I'd approach this the same way you approached buying the business.

I believe FHA was designed to get people into their first homes.

I want to know the cost to design and build  (3 bedrooms 2 bath) two 10 units   5 up and 5 down building in clairmont, Florida and how many square foot of  land i need, I got a group of investor to get this done Average rent depending on design, 1400-1750.

Not looking for a design build firm as I’ll be doing the design.

The most recent HAPCO newsletter had an article regarding "Taking Action Against Squatting".As @Chris K. alluded to, councilman David Oh has introduced Bill No. 170827 to instill an approach to dealing with squatters.