We did Bob the Builder for ds last year--I cut pb&j sandwiches into construction truck shapes, and made cookies and frosted them in the appropiate colors for BTB(didn't bother w/faces--the kids knew who they were lol). I had mini pretzels, cheese cubes, a veggie tray, and sliced fruit, as well as cake and ice cream. For games, we had pin the hat on Bob(copied a pic from coloring book, made hats from construction paper), impersonations(who can spin like Dizzy? Be tall like Lofty?), and "Scoop" the candy(Threw handfuls of candy on the floor and let the kids"scoop" it up.) The whole thing cost us about $40, including the BTB plates and napkins, all the food, decorations, and a few cookie cutters, and the goodie bags(pencils, stickers, etc--all cheap stuff!). We had 6 kids, all under age 5, and they had a good time! Remember--kids aren't as persnickety as adults--they just want to have a good time and eat cake lol!! It's us that worry about having things "just right"
To keep it simple, maybe you could have an evening party and just serve cake and ice cream--everyone will have had dinner by then, and you won't have to deal with a menu! This has served my sil well over the last few years--her two dd's have b-days about a month apart!