A well written management contract should clearly spell out what is expected of both the PMC and the owner, to PROTECT both and avoid misunderstandings.

Simply ask the sponsor if they would be open to connecting you to a handful of investors who have known and invested with them for a long time.

My original plan was to buy 15-20 properties with REI if things went well. 

Determine the cost of construction (hiring a contractor in the GNO area is going to start around $165-175/sqft to build) and be sure to include all holding costs, as well as interest in the loan.

Miami is still doing well, Fort Myers is adjusting and has lower real estate than 12 months ago, etc..)My simple thought, for what it is worth, is choose a place to live and not invest in:  choose the location you and your family WANT to live in ( because of the schools, taxes, weather, other family there, etc...) and then buy and do real estate there (and get whatever licenses you need once you start third party management).I wish you well!

If your leasing application process is thorough and well thought out, and if your lease agreement has been well drafted by your local attorney and if it includes clauses that permit you/your property manager enough latitude to maneuver and anticipate undesirable tenant behaviors, both actions and inactions, and you have operational processes which align with enforcement of your lease, then you've done all you can do to reduce this inherent risk of an undesirable tenant.  

Making such a hasty decision on two weeks worth of knowing these people as your customers seems like a rash decision to me, but I don't know exactly what's going on, and sometimes personalities just do not mix well together.

I have known Brian for many years.

Well that is unfortunate.

I think you have a good start and sometimes you learn more from mistakes than if all goes well.