Hi Jennifer,
Chef Mickey's is a fantastic start to your birthday celebration. Another favorite character dining location is the
Crystal Palace. You'll dine with Pooh, Tigger, Eeyore and Piglet as you enjoy delicious food. My family prefers breakfast at this location. It's never too early in the day to celebrate a birthday though. This past June when I brought my 9 year old there for breakfast, they brought out a cupcake with a candle and a birthday card signed by all the characters. You just have to make sure that your server is aware of your celebration. The character interaction is fantastic at the Crystal Palace and I consider it a "must do".
We really enjoy
Donald's Safari Breakfast at the Animal Kingdom's Tusker House restaurant too. You'll see Mickey, Donald, Goofy and Daisy all decked out in their safari gear. Since you are seeing them at Chef Mickey's too, you may want to save Tusker House for a future trip.
If your little guy is a fan of Disney Junior, he can enjoy meeting his friends at the
Disney Junior Play 'n Dine at Hollywood & Vine.
I hope this helps and that you have a wonderful vacation.
Please let me know if I can assist you further,
Kaylene