Others recommend tools like Stessa or Buildium to track actual costs and project future expenses. 

I've found that there are markets that have a balance of decent cashflow and decent appreciation and that's the type of market I eventually decided to invest in.I'm not too familiar with the different markets down there but I'd highly recommend looking into Candor Realty. 

We've had a couple HVAC techs recharge the refrigerant and one recommended replacing the entire system.

I recommend to everyone. 

I would recommend an STR for the best tax benefits and cash flow no doubt.

Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

BiggerPockets also has a calculator to analyze deals, and I highly recommend you start this as soon as possible, even if you are not ready to buy.

I recommend getting some help to make the process easier. 

Quote from @Bob Avery: I don't recommend leaving a space blank because someone could later attempt to add something in.

For jacksonville I would highly recommend Elenis at Thirdstone Properties.