Looks like that's a standard public access to public beach.
You can bring your own stuff, although vendors have been known to lie. Vendors do not have any special rights or privileges outside of private beach. There is a vendor zone, but you are not restricted from that zone, they are limited to it and it's usually defined by smaller PVC pipes placed near the dune.
Tents are required by county ordinance to remain on the upper 1/3 of the beach and the 10x10 limit remains. To be honest this is rarely enforced and unless it's really busy people use them closer to the beach.
You can always reach out to Beach Code Enforcement or the TDC. I would recommend programming beach code enforcement in your phone just in case.
Code Enforcement:
www.co.walton.fl.us
Tourist Development:
See more about the groups that make up the Tourism Department
www.co.walton.fl.us