WE have sailed at that time to those places, & generally you get great weather. We have however had a trip to Barbados in torrential rain, but just put up with it! Ships will generally avoid any hurricane destinations & visit somewhere else, they are very good at missing out on severe weather. All the islands you mention are beautiful, especially unspoilt Dominica, so good luck.
Did this cruise last November, and are sailing again on the cruise you are going on. The only rough weather was coming home after sailing out of Madeira, due to bad weather, but it wasn't too bad, we were unfortunate in having a cabin at the front of the ship, so this time we've gone mid-ship so any disturbance should be minimised. the weather in the Caribbean is fantastic, make sure you take a hat if you go on any excursions. Maybe we'll see you.