I'm not sure what the regulations are down in Florida, but in Indiana you MUST apply for a permit from the Department of Natural Resources AND the Army Corps of Engineers. These permits took about 5 months to obtain.
I certainly didn't expect all of the red tape for my seawall because I live on a small inland lake with waves averaging 6 inches on windy days! We do have the freezes to deal with though.
The DNR in Indiana is big on natural materials like stone, but frowns upon concrete and won't allow wood. The stones and boulders provide little hiding places for animals. I suggest checking with the State of Florida before you even design anything. It will save you of time in the long run.
Up here, I've seen seawalls made out of concrete, wood, railroad ties, steel, plastic and piled stones, The only one that seems to last is the stone seawall. All of the others get smashed by the ice in a matter of 5 years. The stones move under pressure, and can be picked up and moved back into place every few years.