Hi Laura,
It sounds like you have a great start on planning your vacation! Let me share some of my favorite character meals with you for dining with young children.
When my daughter was a preschooler, we really enjoyed
Disney Junior Play 'n Dine at Hollywood & Vine at Disney's Hollywood Studios. Not only do you get to dine with characters, but little ones get to get up and dance to fun music as well! Characters here include Disney Junior favorites such as Jake the Neverland Pirate and Special Agent Oso. This experience is available at breakfast and lunch.
Another character meal that my family really enjoys is Donald's Safari Breakfast and Lunch at
Tusker House Restaurant in Disney's Animal Kingdom. At this meal, Donald Duck and his friends appear in their safari gear. I really like that this meal includes both African fare for those with adventurous palates, as well as more traditional American breakfast and lunch items for those who do not have exotic appetites.
For something a little different, try
Mickey's Backyard BBQ at Disney's Fort Wilderness Resort and Campground. This fun dining experience is held in an outdoor pavilion. The fare is typical BBQ fare such as ribs and corn, and the entertainment is great. There is signing and dancing with characters, and when we went recently, there was a cowboy doing roping tricks. It was a really fun time!
Please know that at these experiences, characters are subject to change. Have a great time planning your trip Laura, and please do not hesitate to ask if you have any further questions!