Hi Lauren,
All three resorts that you are considering are fun in their own way. Let me offer you some thoughts that might help with your decision.
First, though it does have a lovely theme, my last choice of your three would be
Disney's Caribbean Beach Resort. You mentioned that you were considering two standard hotel rooms here, and I believe that the other resorts have more to offer in either theme or layout your family.
Disney's Art of Animation Resort has a lot to offer. The larger-than-life theme is bold and appealing to many young children. The Big Blue Pool is the largest pool at Walt Disney World, and features a zero-depth entry. You can hear music underwater at this pool! The family suites include a separate living room and bedroom, which means that if the kids need to nap or go to bed early, the adults can still have your own space. There is a kitchenette for snacks and breakfast, and two bathrooms.
I very much enjoy
Disney's Old Key West Resort. The theme there is laid-back and relaxing, so you will have to determine if you family will respond to this. I would recommend that at Disney's Old Key West Resort you consider a one-bedroom villa. It will give you considerably more space than a family suite at Disney's Art of Animation Resort or two hotel rooms at Disney's Caribbean Beach Resort. There is one bedroom, a very large living area, and one bathroom. You will also have a full kitchen in which you could prepare entire meals, and laundry within the villa.
I hope that these thoughts are helpful for you in making your decision, Lauren. Please do not hesitate to ask if you have any further questions!