Are there typically tent sites available in March? Called about reservation but don't take reservations on tent sites.

I would say yes. It doesn't ever appear full.

Yes but you have to make the reservation on time

Best thing to do is to either bring your own tents and install it or get someone going there and inquire about the size of tents you can deploy there. There are companies that rent tents for these occasions.

Seems like it. Winter is VERY busy in South Florida.