Welcome Andrea! Thanks for stopping by the Disney Parks Moms Panel.
I have never heard of any place at Walt Disney World Resort where real passports could be stamped. I believe cast members are not allowed to stamp real documents or any type of passport that is not the souvenir one sold at Epcot. The World Showcase Passport can be found at many merchandise locations throughout Epcot and it will certainly become a great souvenir of your magical vacation.
Regarding
Mickey’s Not-So-Scary Halloween Party, you have the right information. Guests with valid ticket for the party are allowed to enter Magic Kingdom Park after 4:00 p.m. and they can be wearing their costumes at this time.
Please note that for safety reasons, Disney created new guidelines for wearing costumes at the parks. You can find a
list of the costume guidelines at Disney official website or at the
Disney Parks Blog, where an informative video about Costume Guidelines for events at Disney Parks has been posted recently.
Hope this information helps. Please, let us know if you have any additional questions.
Have a magical day!
Gina V.