February is a perfect time of year to go on any Caribbean itinerary. We've been to St. Thomas, St. Maarten, many times in January and February, and have always had fabulous weather. The Bahamas, being a tiny bit more north, are still often plenty warm enough for swimming then too.
But if the weather is a concern, any southern itinerary is great at that time of year too. That would be my own preference. The weather is always very warm there.
As a totally personal preference, hubby and I weren't terribly fond of Belize. Kind of a bore. (Although the river tubing sure sounded like fun. Hubby wasn't up to it then.)
Be aware, that a lot of people really don't like Jamaica. Myself among them. I feel totally UNsafe there. Such a shame that a naturally gorgeous island like that has been made so undesirable by the people in the port cities.
On the other hand, the Legend is a great ship, one of our favorites, for sure. And we totally love Cozumel, even after being there several times.