As an 8-year veteran of Blue and Gold cake bakes (well, of course the Scouts and dad did it, but I was an event organizer!) here are some of the categories we used in our Pack:
Biggest cake
Smallest cake--my older son won this category one year for making a mini-cupcake!
Best fits the B&G theme--whatever that is this year
Best Scouting theme
Ugliest cake--Scout MUST state upon contest entry that he wants his cake in this category!!!!!
Best cartoon cake
Best food cake (looks like hot dog, hamburger, etc)
Judges' Choice--best of the best
Our Pack insisted on the cakes being TOTALLY edible--no Lego characters or toothpicks holding things together or anything. For the birthday of Cub Scouting a couple of years ago, my younger son made a birthday cake--sheet cake decorated in Cub Scouting's colors and complete with candles--those pirouette cookies topped with orange fruit roll-ups!!!! Totally edible--and he got Judges' Choice. It looked great and tasted pretty good, too! (Not that we did a taste test--it was strictly appearances--and Mom couldn't help at all--it was a Dad/Son event.)
Our prizes were trophies and Cake Bake patches that we ordered from patch.com I'm not sure how kitchen items would go over with a Tiger or Wolf Scout. But everyone loves a patch!!!!! Especially if they have the red vest to show them off! One year the Pack tried certificates and the kids were disappointed. Maybe some prizes from the Scout store???? They have cool fold-up eating utensils that they may like--perfect for camping!
Good luck!!! I look back with great love on my Cub Scout days!!!!