Hi, Ann! I did a really quick search for some of the restaurants that feature characters during the dates of your trip, and I do see availability for places such as Cape May Cafe for breakfast, 'Ohana for breakfast, Hollywood and Vine for breakfast and lunch. There is also some availability at Tusker House for dinner and Garden Grill for dinner. I assumed 6 guests, and I didn't check specific times, so obviously, my results may be different, but if you can be somewhat flexible, you may be able to find something. My best suggestion is to head to
Disney World Dining Reservations and do a search for character dining experiences.
As for which order you should do the parks, first, if you don't have park hoppers, plan around the dining experiences you are able to get. If you get something at Garden Grill, plan EPCOT for that day. If the dining reservations don't matter, you may want to go to the park that has extra magic hours in either the morning or evening to extend your theme park time.
If you won't be using extra magic hours, so it doesn't matter which park which day, Saturday is always my favorite day at the Magic Kingdom, and since it's the last day of your trip, it's such a great way to end a magical vacation! I'd probably start with EPCOT, then choose either Disney's Hollywood Studios or Animal Kingdom for Friday.
I hope you have an awesome vacation!