In my part of California, a 2 unit (or 2 home) property with only one meter is a red flag that one of the units/houses is not permitted.

Values can be high, but zoning, planning, permitting, etc... in Forsyth can take YEARS there. 

Getting the permit for rental was costly, tricky and a lengthy process.

I was thinking about going at it alone and once permitted, I would remote manage.

You do not necessarily have to replace sheet rock that only has like smoke, but it will all need to be cleaned and any with heat damage or extensive smoke damage will need to be replaced.You are on the right track with getting the city involved--pull permits and "jump through the hoops"  You want to be able to demonstrate for a future buyer that you did everything you should have and the city signed off on it.  

Fix the outstanding permit issues, (fix leaking gas pipe, prove basement original/make it uninhabitable) update panel, FIGHT CITY TO KEEP BASEMENT.

., the dumpster and pulling the permit. 

Being licensed only goes so far unless you have them pull the permits... 

when I initially did the Appraisal they estimated my house is 1000 sq ft on a 7700 sq ft lot but in the back of my house connected I have what they turned in to a living room an additional 900 sq ft  that was not included on my appraiser because it was not permitted.

@Milagros Aspillaga Developing in Miami is tough and you have to know what your doing when dealing with Zoning, City Permits, Contractors, etc.