Hi there, Catherine! Before I give you my recommendations for dining, make sure you take a look at other ways to
Celebrate Your Special Occasion. Be sure to stop by the front desk of your Walt Disney World Resort for a
Happy Birthday button for your son. These can also be found at Guest Services locations in the parks. I'm sure he'll feel so happy getting that special recognition from people at every turn. You can also phone (407) 827-2253 at least 48 hours in advance to order a specialty birthday cake for your son. Definitely let them know of your son's peanut allergy when you order.
Judging by your choices so far, it seems like you are looking for a character dining experience. There are no characters for dinner at Tusker House Restaurant. The Garden Grill Restaurant at Epcot offers dinner featuring Chip 'n Dale's Harvest Feast. It's a fun experience in a restaurant which slowly rotates while you look at the Living with the Land attraction. Plus, you're among many exciting experiences right inside Epcot Theme Park. Although it's not a character dining experience, I think you would all love dining at Whispering Canyon Cafe at Disney's Wilderness Lodge Resort. It's a slapstick dining experience and loads of FUN. Be sure to tell your server about your son's birthday!! Lastly, if you really want to dine at Chef Mickey's, keep checking back. Call (407) WDW-DINE daily, if you are so inclined. Reservations change often, and you might get lucky.
I hope your son has a wonderful birthday, and I wish you a MAGICAL vacation!
-Jacqui