Sounds absolutely perfect to me! The Baths in Virgin Gorda are very unique, very picturesque, and I hope you have a great time there. I hope there's a plane landing when you go to Maho, it's almost on top of you, really fun. St. Lucia is a beautiful island, I think you will enjoy touring there. I'll almost bet your snorkeling trip in Barbados will be with Tiami. Their catamarans are beautiful, big, clean, and a great crew. We've seen loads of turtles on our snorkels. Then they'll take you to a nice beach to enjoy some rum punch, swimming or just relaxing. I hope you see many whales and dolphins in Grenada, do try to go over to the Grand Anse beach, it's white powder and just so relaxing. The Curacao tour sounds marvelous and I think you'll enjoy that. Aruba has some fantastic beaches, we went to Palm Beach the last time we were there. The beach was not crowded, there was a pier that had a bar/restaurant, they had water toys, and there were a couple of hotels that you could get drinks from, too.
You have a wonderful itinerary, and Celebrity is supposed to be fantastic. We'll find out soon and will let you know when we return.
Be sure to bring extra memory chips for your camera, batteries too. If you're like me, extra film as well. I still like my 35mm. We do have a digital and a camcorder, but I like my old 35mm. Don't forget the sunscreen either or your sunglasses