For the eyes: Snip each mini marshmallow in half with scissors. Press a mini chocolate chip into the cut sides of the marshmallows as a pupil for each eye. Set aside.
For the ears: Set the red gumdrop fruit slices on the work surface on their rounded side or upright. With a small sharp knife, trim one-third off the side of the gumdrop (to decrease its weight). Reserve the trimmings. Then cut through each slice vertically about three-quarters of the way through. Twist the top half away from the bottom half and press the parts together at a 45 degree angle (they will still be attached).
For the tails: Slice the reserved trimmings from the ears into 12 thin strips about 1 inch long.
For the trunks: Remove a 3/4-inch segment from each gummy ring to make a trunk.
To assemble: Frost each cupcake with about 2 tablespoons of the buttercream. Place the pink sanding sugar in a small bowl. Invert each cupcake into the sugar and press gently to adhere.
Attach the eyes by pressing gently into position. Insert one end of the trunk just below eye level. Push the bottom half of the ears into the sides of the cupcake. Insert a tail on the back of the cupcake. Repeat steps for all cupcakes.
A cupcake carrier, designed specifically for the job, is a great help when transporting decorated cupcakes. If you don't have one, prep all the trunks and ears and eyes ahead of time, and assemble them when you arrive.