Melt cocoa, peanut butter and white Candy Melts following package instructions in bottle, decorating bag or parchment triangle. In monkey baking pan, use melted cocoa and peanut butter candy to fill facial details on monkey. Refrigerate until set. Add melted white candy to eye section; refrigerate until set. Fill pan 1/2-3/4 in. high with melted cocoa candy. Gently tap mold on the counter. Refrigerate until firm. Carefully remove candy from mold. Attach 2 dowel rods to back of monkey with melted candy, leaving 4 in. extended to stick into cake. Let set.
Pipe color details in molds using melted candy in parchment bag with small hole cut in tip. Refrigerate until firm. Fill remainder of mold with melted candy; do not insert sticks. Refrigerate until firm; unmold.
Bake and cool 2 - 15 x 11 in. diamond cake layers; remove from pan and cool completely. Place on foil-covered cake board. Spatula ice sides in yellow buttercream; ice cake top with white buttercream.
Pipe tip 6 bead top and bottom borders. Attach small monkey candies and jumbo confetti sprinkles to sides of cake. Insert large monkey candy on dowel rods into cake.