I just did a Mickey party for my twins turning two.
We did hot dogs "hot diggity dog" with a big topping bar. I made several toppings, (slaw, several types of onions, and hot sauces) plus had the classics (relish, mustard, kraut etc). A few classic sides mac and cheese, potato salad etc.
For the cake, I wasn't as ambitious as you. I baked 6 round cakes, (to make a 2 layer cake) and then trimmed four down to use as ears. My cake and invites looked something like these
http://www.etsy.com/listing/67093926...ge=6&ga_facet=
I did the black with buttercream and the red with fondant.
We did the mickey cookies for a favor. I didn't let my guests decorate...many of them were young.
We didn't do much in the way of activities...but we did have the MMCH theme song and had a dance "contest".
Have fun!