Special equipment: a silicone baking mat, two 6-inch bamboo skewers, 2 corn on the cob holders and an 8-inch round cooling rack
For the hot dogs: Unwrap the salt water taffy and caramels and place on a microwave-safe dish. Microwave until slightly softened and a little pliable but not melted, about 10 seconds. Knead the candies together to blend into a uniform pinkish color. Divide into 2 equal sections and roll each piece into a hot dog shape. Freeze for 2 hours to harden.
Using the food coloring marker, add "grill marks" to the hot dogs.
For the grill cake: Bake two 9-inch cake rounds according to the cake mix box instructions, then let cool completely. Trim the cake tops, place on large plate and frost with the chocolate frosting.
For the coals: Preheat the broiler on low. Line a baking sheet with a silicone baking mat and spray with nonstick cooking spray.
Arrange the mini marshmallows on the prepared baking sheet in a 7-inch diameter circle (the marshmallows will melt together and form a disk). Place under the broiler until the marshmallows are slightly charred, 1 to 2 minutes. Let cool completely.
For the cheeseburgers: In a medium pot, combine the marshmallows, chocolate chips and butter and heat over low heat, stirring constantly, until the marshmallows and chocolate are melted. Remove from the heat, stir in the cereal and vanilla and mix until completely combined. Form into patties. Cut the fruit leather into 3-by-3-inch pieces and arrange on top of the puffed rice cereal patties.
For the kebabs: Thread a slice of the lime and orange candy onto a 6-inch bamboo skewer, followed by a gumball and then a lemon and cherry candy slice. Repeat with the remaining candy on a second skewer.
For the corn on the cob: Slice off the ends of the cream-filled sponge cake. Frost the outside with the vanilla frosting, leaving the bottom unfrosted. Press the jelly beans into the frosting to form corn kernels and continue until completely covered. Insert a corn holder at each end.
To assemble: Place the disk of marshmallow coals on top of the cake. Sprinkle the rock candy in between the coals. Place an 8-inch cooling rack on top. Arrange the hot dogs, kebabs, corn on the cob and cheeseburgers on top of the cooling rack.