A movie birthday theme offers a lot of flexibility in terms of activities. You could play dress up games, actually make mini-movies, or even play charades. Cut mini marshmallow in half and pinch back together for popcorn
Candy cane marshmallows for hot cocoa. Stick a vegan candy cane into large vegan marshmallow. Dip marshmallow in melted chocolate. Roll into crushed vegan candy cane. Place on a waxed paper lined baking sheet and allow to set.