We have the apple and ice cream bar in our cars and they are cute and smell good. The smell only lasts about a month, but I still use it to add Disney to my car. Today you can get free shipping since it's a park item, use code parkfree!
The merchandise discount at WDW is 10% and not too many food discounts are available at WDW. You should be able to upgrade your park hopper to an AP at DL then upgrade your AP to the Premier at WDW with no problems. To be safe, just call WDW ticketing directly. Your Premier AP will keep the original expiration date of the DL AP. It's a great pass if you visit both DL and WDW!