We spent a good majority of our early honeymoon at the literal beach. November in Miami isn’t super hot but definitely warmer than the rest of the country. Miami Beach actually is its own city, separate from Miami. Basically its own island separated by a bay.
You could wear any type of swimsuit and feel fine. Water was a bit too cold for my liking though. Our hotel had an outdoor pool, so I did my swimming in it. I do wish Miami water was as pretty as I hear it is on other side of Florida. Seashell collectors would most likely be let down here.