I'll try to answer a few of your questions as best as I can. I didn't know Tampa had direct flight in the past to St. Martin. Must have been a while ago. As long as you don't have a connecting flight then MIA should be fine. Global entry doesn't matter when departing Miami, so I would simply plan to arrive at the airport two hours ahead of time. Usual stuff like baggage check, security screening, etc.

Coco Beach is gone and KKO (Kakao) is relatively close to where Coco used to be. So, the light blue color of the umbrellas are now dark blue up that way. But, the good news is that there is a very good bar/restaurant up-and-running though a little pricey. $30 USD will rent two beach chairs and an umbrella. The old nude section up there was actually kind of out of place, IMO and KKO does't have a section like that.

The Paradise View restaurant is also long gone, but I have no idea about it's future plans. However, it's still a great view from up there and you can see St. Barths!

Villa Pizza is also history as another post above has indicated. That's too bad because it was a good place to catch a bite when up that way.

Hope this helps.