If you are crafty, you can make dry erase boards out of a shower board you get from the hardware store. Simply cut into the sizes you want and cover the edges with bright colored tape. Give each kid a dry erase marker and old socks work great for erasers.
Fill the goodie bags with smarties and dum-dums. Dollar tree normally has the huge pencils and erasers for "big mistakes".
You could also do the press on mustaches if the kids are going to ask the questions.
Sounds like a very fun party!