Transfer half of each frosting to separate decorating bags (one each for vanilla, dark and milk chocolate). Starting with a variety of cupcake sizes, spread tops with a base color.
Make flourishes with decorating bags fitted with writing or basket-weave tips. For simple designs, use the writing tip to outline or divide, then fill in by spreading frosting with spatula. For thick stripes, use the flat basket-weave tip; finish with candies. Store cupcakes in airtight container in refrigerator for up to 1 week. Let stand at room temperature for 20 minutes before serving.