I do not believe the restaurants do anything special for the holidays (except for Thanksgiving Day and Christmas Day they have special menus) but you can book the Candlelight Processional Package. With this you eat in a certain place and you get special seating at the Candlelight Processional. You must ask for the special package - just eating at a certain restaurant does not give you special access.
Following is info I got off a website about Christmas in Epcot. We have done this a few times and it is wonderful.
You can enjoy Holidays around the World. Bedecked with all the holiday trimmings, this theme park is filled with enchantment. The center walkway that links Future World and the World Showcase is spanned by the "Lights of Winter." As evening descends, these lights transform into a dazzling musical display that twinkle and "dance" to inspirational holiday music. For an added treat, watch as the fountain performs in step with this glistening interlude.
There's a spectacular Christmas tree with decorations that pay homage to all of the countries that comprise the World Showcase. Every evening, you can join Mickey and friends for the nightly tree-lighting ceremony. The approximate length of this ceremony is 10 minutes.
Each country has it's own special theme that highlights it's culture. Storytellers will delight you with tales of their heritage and how the holidays are celebrated in their homeland. It's a unique opportunity to learn more about the world in which we live.
There's nothing that's more inspirational than the nightly Candlelight Processional. This beautiful show evokes the true meaning of the holidays and is not to be missed.
Illuminations is enhanced for the Holidays. "Let There Be Peace On Earth" with narration by Walter Cronkite will be the finale of this amazing nightly show.
Linda