In advance: Make heart topper. Tint fondant violet and roll out 1/16 in. thick. Cut one heart for each treat using medium Cut-Out; let dry on cornstarch-dusted board.
Bake and cool 1 in. high cake using firm-textured batter such as pound cake; freeze. Cut 2 1/2, 2 and 1 1/2 in. squares with knife. Cover cakes with melted candy; let set. Seal bottoms with additional melted candy using a spatula; let set on waxed paper-covered board.
Use patterns to mark holes; cut out holes using tip of hot knife. For each treat, cut 8 lollipop sticks to 3 1/4 in.; insert sticks in cakes to form tower. For bottom separation, following placement pattern, insert lollipop sticks into bottom of middle cake and top of base cake. For top separation, following placement pattern, insert lollipop sticks into bottom of top cake and top of middle cake. Roll out fondant 1/8 in. thick. Cut 1/8 in. wide strips; attach around cakes with damp brush.
Cut fondant flowers using pansy cutter from Flower Making Set. Cup slightly with modeling stick and attach using melted candy in cut parchment bag. Pipe tip 3 dot centers with buttercream. Cut a lollipop stick to 2 1/2 in.; attach to back of heart using melted candy leaving 1 in. extending at bottom. Cut small hole in center of top cake;insert heart.