From my initial research we would get a 3b2b, 1700-2000sqft in a good school district and rent for around 1800-1900$.

You get grandfathered into the codes that were in place at the time, you get the old setbacks, you don't pay an architect, engineer, city and permit fees, plan check costs, school fees and other costs that will not come with an existing house.Not saying that you can't build new for less than a remodel, but not usually when you add in all the costs above. 

Looking in good commuters areas with best schools.

Are you able to tell which ones are the A class, B class, and C class properties based on how much it is being sold for and what types of public schools are available in the area?

I’m not buying for the school district and amenities these neighborhoods have.

What is the permit cost and school fees?

There's a law school in my town and they do this as a senior project every year- take landlords to court for fair housing and relish in getting them fined.

One thing to consider if possible is to pay attention to the schools in the area and try to buy in an area with a higher school rating.

I got fancy with the title and called it HOW TO BUY MOBILE HOMES lol  Writing a book was always on my crazy goal list because I was not the brightest kid in school and I like to do what people don't think I'd ever do. 

South Tampa, including Hyde Park and Palma Ceia, remains a top choice with its high-end homes and excellent schools.