In advance, tint portions of fondant yellow, rose, violet, blue and green; roll out 1/8 in. thick. Cut a variety of yellow, rose and violet flowers using large, medium and small Cut-Outs. Dry all large and half of the medium flowers in each color on waxed paper covered board, dusted with cornstarch. Shape all small flowers and the remaining half of the medium flowers using the medium ball tool from confectionery set on thick shaping foam. For flower centers, roll a 1/8 in. white ball and attach to center of cupped flowers with damp brush. Let dry in melting plate cavities dusted with cornstarch. Cut leaves from green fondant. Make extras of each size to allow for breakage.
Bake your favorite 2-layer cake recipe or mix following recipe instructions in 6 in., and 10 in. pans. Cool layers in pans on wire rack 10 minutes. Remove from pan and cool completely. Arrange each size cake on a separate foil-wrapped cake board. Prepare for stacked construction. Lightly ice each cake in buttercream icing to prepare for fondant covering.
Roll out white fondant 1/8 in. thick. Cover cakes; smooth. Using wavy-edge wheel of Cutter/Embosser, score diagonal lines on each cake side, 1-1/4 in. apart. Pipe tip 3 buttercream dots at intersecting points. Pipe tip 4 bead bottom borders.
For large flowers, attach a cupped medium flower to large flower with thinned fondant adhesive. For small flowers, attach small flower to flat medium flower. To make bouquet, attach 9 to 12 assorted flowers to 9 in. pieces of wire with adhesive; let dry. Arrange wired flowers facing forward; tape together with florist tape. Trim wires as needed. Insert bouquet in flower spike. Attach leaves to bouquet with adhesive.
At the celebration, stack cakes. Insert flower spike in center of 6 in. cake. Attach remaining flowers and leaves to cake sides with dots of icing.