If I do the work unpermitted by a licensed contractor, is it illegal to advertise it based on the added bedrooms?

I will continue my homework based on your recommendations.

This will cover the mortgage payments. all of the additional expenses I will cover out of pocket (escrow account).

An additional benefit of a detailed engineering-based Cost Segregation Study is that it can increase potential insurance premium savings as well as provide support for the property tax appeals process.

Often it is based on how well you pay back history.

Could be a win/win situation if you purchased and offered additional funds to move them out.

Based on my research it seems like with a little rehab and managing a short term rental effectively, short term would likely cash flow more in a market like Tampa. 

Plan is to add two additional units to the bottom floor and remodel the upstairs unit. 

That being said never base your offer on the other guy.

Additionally, Beaver Falls is relatively convenient to navigate to the city and other areas, a 15-20 minute drive to the airport, and easy access to 376.