Hi Danying!
Welcome to the Disney Parks Moms Panel! Your Walt Disney World Resort vacation is less than a month away, you must be getting SO excited!! And you're visiting during the Holidays, too! Definitely check out the seasonal foodie fun at the
Epcot International Festival of the Holidays, as well as the
larger than life gingerbread displays that can be found around the 'World.
This past March I surprised my family with tickets to this very
Fantasmic! Dessert & VIP Viewing Experience that you just booked. To help ease the flow of traffic, the "reservation" times listed for this event are actually staggered check-in times, which eliminates a long line just before the show. The actual process of checking-in and getting your treat box takes about 15 minutes max, after which you're allowed to go find seating within the VIP section.
There is a huge gap of time between your reservation and the actual show starting. While you could technically check-in later and be fine, if everyone did that it would create a back-log, and delay others who had later 'reservation' times. Instead, you can always check-in and pick up your treat box, then leave the theatre to come back about half an hour or so before the start time. The seating section is massive, so you won't have a problem finding seats. And you'll be issued credentials that will speed up your reentry. However, should you decide to stay in the theatre, there is a restroom as well as concession stand should you need more treats to eat.
We'll See You Real Soon, Danying!
~Kristen