Hi Samantha,
Thanks so much for stopping by the Disney Parks Moms Panel with this great question! You're going to be visiting Walt Disney World during the most magical time of year, and
Mickey's Very Merry Christmas Party is a great way to celebrate the holiday season!
I recently attended the Christmas Party myself and loved every single minute of it, from Mickey's Once Upon a Christmastime Parade to seeing snow on Main Street, U.S.A. to those yummy holiday treats you mentioned. There are 7 locations around Magic Kingdom where you can pick up those complimentary goodies and all have alternate options available for special dietary needs. This year, in addition to cookies and hot cocoa, apple slices and apple juice are available as standard offerings. If you ask, vegan chocolate chip cookies and sugar-free hot cocoa are also available. Unfortunately, it doesn't sound like a vegan hot cocoa option is available, but you could always make a stop by Starbucks in Main Street Bakery, where they can brew you up a cup of Christmas cheer - as you probably know, most of the drinks they offer can be made vegan by ordering them with soy milk. Those drinks aren't included in the price of your ticket, but might be a great option if you don't want to take your own treats into the park.
Be sure to pick up a Party guide when you enter the park for information on all the merriment, including the locations and hours of those treat locations.
Have a holly, jolly time during your visit, Samantha! Please write back if we can help answer any other questions.
Beth