Hi Melissa,
Traveling to Walt Disney World with little ones does take a little more careful planning. However, I am glad to hear that you are thinking of these sorts of situations so that you are prepared during your magical trip.
The
Baby Care Centers in each of the four theme parks are a fantastic resource. They are a quiet escape from the hustle and bustle of the theme parks. They are stocked with baby essentials such as formula, diapers, baby food, and even clothes for purchase, if there is a emergency need. I am happy to tell you that each time I have visited one, although I have not been to all four, they have had bottle warmers or microwaves for heating up bottles or baby food. I will tell you that the one at Disney's Hollywood Studios is the smallest and wasn't as stocked as the one in Magic Kingdom. However, I do remember it having a microwave. See the attached video for more information.
Having traveled with infants on many occasions, I too, had to heat bottles during mealtimes at a dining location. The cast members were always very willing to bring a large class or mug of hot water. One tip from experience, though, is to make sure to let them know not to fill it up all the way, just in case you are putting the bottle IN the glass of hot water, to heat up that way. Otherwise, it will overflow.
I wish you a magical trip. Enjoy all those special moments watching the wonder and joy through their tiny eyes.
~Allison L