Devil's advocate here, because I can hide behind a screen and keyboard and you can judge me all you want.
Don't do it. You're paying a lot of money for a vacation for an infant who won't remember it. You're not going on vacation....you're moving your normal family routine to a ship. Sure you don't have cook and clean, but that child will still need your 100% attention. You're paying extra for babysitting. When they're 3, they can go to the clubs for free (as in, you paid a boatload of money to have a great vacation and this perk is included). You are limited in your alone time. You're very limited in your excursions. If it's possible, let the grandparents have their time with the baby and you and your wife go on a great vacation and enjoy your time with each other. You have plenty of time in the near future to enjoy great Disney vacations.
I know I'm going to catch hell for this response but like I said, you don't know me from Adam and I just wanted to give you the "other side" of things.