Contractor Recommendations for a total rehab

[Mo Gangidi]

Folks I recently bought a property in Northside of Jacksonville, FL. The property needs a total rehab. The roof came apart and mold all over the house. Everything has to come down including sheetrock etc. Only the concrete side walls remain. I am looking for contractor recommendations and also where to look for them? Is it a good idea to give everything to one guy/company so lesser headache or split them to different contractors? I did flips before and worked with contractors individually but this project is a total mess and a good learning so I am excited but nervous to find the right people for the job. 

This property is built in the 50s or 60s and the building codes have changed a lot, how to approach county to get this info? or is it the responsibility of the contractor?

Since most of the stuff is taken out, do I need mold restoration done? I assume some of the framing may remain but not sure.

One contractor gave me a fairly good price but unfortunately he doesn't seem to licensed. Would it be sensible to pursue him? He came with a reference from another investor who got his roof done with him. I can check for more references but am a little nervous to move forward if he is unable to produce license and show worker's comp for his employees. 

Nail in coffin, this house has septic tank, anything needs to be done for it? I checked with city and couple of other septic tank folks, they mentioned, you don't call unless you have a problem. Is that true, any experience for any of you?

Sorry if the post is too long but I really need some answers before I take a dive.