Hi Mimi!
I have two great suggestions for you:
Chef Mickey's offers an incredible buffet that is a perennial favorite of Walt Disney World guests. Mickey and his friends visit while you dine on the Contemporary concourse with monorails passing nearby.
'Ohana, at the Polynesian, offers a great family style breakfast you can enjoy with Stitch and his friends.
Since both of these are in the Magic Kingdom area, your best bet will be to travel from the Art of Animation to the Magic Kingdom via Disney World bus transportation. From there, you can easily walk to the Contemporary via the footpath or use the monorail or boat to head over to the Polynesian.
I'd suggest a 9:30am or 10am breakfast at the latest. This should give you plenty of time for travel.
Hope this helps you plan a wonderful last day at Walt Disney World!