Hi Sheri,
You are going to be the coolest Mom in the world when your son hears about this surprise!
Mickey's Not-So-Scary Halloween Party (MNSSHP) is incredible & I can't wait to go back this year!
All of the candy is individually wrapped but if your son has a nut allergy I would not risk it. Disney World really goes above & beyond to meet as many dietary requests as possible. I had some friends facing a similar situation last year. They sent an email to
SpecialDiets@DisneyWorld.com. They have a form they can email you to fill out & return to them regarding your son's allergies. You'll also need to be sure & let them know which night you will be attending MNSSHP. Make sure you give them at least 14 days advanced notice. Once they receive the form, they will notify the event Coordinator & City Hall in the Magic Kingdom. When you arrive for the party, you can go to City Hall & pick up some "safe" candy for your son. All part of the Disney magic!
In the alternative, you could take some candy. However, I really wouldn't worry about taking a lot into the park. My boys had fun trick-or-treating but only ate a couple of pieces while we were in the park for MNSSHP. There were so many other great things going on that they really didn't stop to think about it during the event.
Wishing you minnie magical spooktacular memories :-) Allison