With offset spatula, spread about 3/4 cup buttercream onto each cupcake, leaving bottom 1/2 inch unfrosted; smooth frosting into ball shape. Starting at top, gently press candy chocolates into frosting, covering sphere to make "golf-ball dimples." Refrigerate until firm, 15 to 30 minutes.
Make tees: Microwave coating chocolates, 1 color at a time, in heatproof bowl on high 30 seconds; stir. If not completely melted, microwave in 10-second increments, stirring after each. Stir until smooth. Pour 1/2 cup into champagne glass; tap glass on counter, and rotate slowly to coat evenly. Repeat with remaining 11 glasses. Refrigerate until set, 30 to 45 minutes.
Gently set unfrosted cupcake bottoms into coated tees. Serve immediately or refrigerate up to 5 hours.