Hello Rebecca,
The magic is right around the corner for you and your family! Although I love both of those resorts, I would recommend Disney's Caribbean Beach Resort as its theming might be more appealing to your sons. The pool is fashioned after a spanish style fort complete with waterslide, water cannons and zero entry entry pool. You might even be able to book one of the specially themed "pirate rooms". These rooms really offer a unique experience as the beds are fashioned after pirate ships and the tables and furniture look like crates and barrels offering a really fun and different twist to the typical resort room.
In regards to an evening of entertainment, I would suggest the Spirit of Aloha dinner show rather than Downtown Disney. Boys of an older age might get more out of the atmosphere in Downtown Disney. Although, bowling at
Splitsville Luxury Lanes or time at
DisneyQuest could be entertaining for the older two, but not as much for the infant. Another dinner show that my family simply loves is
Mickey's Backyard Barbecue at Disney's Fort Wilderness and Campground. I think all of you would really love it. The dancing, music and food are super kid and family friendly and lots of fun! My kids were giggling and smiling the entire time. Keep in mind your budget and your boys interests to make that final decision.
Have a magical time. It'll be here before you can say "supercalifragilisticexpialidocious!"
~Allison L