1 week in advance: Make gum paste trims for cake top.
Tint gum paste: 18 oz. yellow, 8 oz. orange, 4 oz. light violet, 2 oz. dark violet; reserve a small amount of white. Roll out 1/8 in. thick unless otherwise specified.
Using patterns, cut out yellow moon with tree in 1 piece. Set on cornstarch-dusted board. Cut orange tree; attach over yellow base using Gum Paste Adhesive. Use cutter to cut out pumpkin; set on cornstarch-dusted board. Roll out violet 1/16 in. thick; use pattern to cut out owl. Attach.
For trims, roll out gum paste 1/16 in. thick. Cut thin yellow and orange strips for pumpkin lines, white eyes for pumpkin and owl, light violet pumpkin nose, mouth and irises, dark violet owl wings, bow tie, nose and pupils for pumpkin. Attach all using Gum Paste Adhesive. Let dry 1 week.
When dry, attach Lollipop Sticks with melted candy. Carefully turn gum paste pieces over onto waxed paper-covered cake boards. Attach three 3 in. lengths where tree branches connect to moon and on upper trunk section. Attach 6 in. length to tree trunk and 5 in. length to pumpkin, leaving 3 in. exposed at bottom to insert into cake. Attach two 8 in. lengths to back of moon, leaving 5 in. exposed at bottom.
Bake and cool 2-layer cake (bake two 1 1/2 in. high layers for a 3 in. high cake). Tint fondant: 34 oz. green, 16 oz. orange; reserve 3 oz. white. Roll out 1/8 in. thick as needed, unless otherwise specified. Prepare and cover cake with 24 oz. green fondant.
Use cutter to cut pumpkin stem; cut out 1 in. long leaf shape. Cut thin strips for stem and leaf details and attach using damp brush. Reserve remaining green. Tint a small amount of icing dark violet; pipe tip 1 eyelids. Cut 32 x 3 in. high orange strip; attach around cake using damp brush.
Roll out white fondant 1/8 in. thick. Using narrow end of tip 12, cut 300 white dots; attach in 5 staggered rows, about 1/2 in. apart. For grass, roll out reserved green 1/4 in. thick. Cut 18 assorted strips, 1 in. to 4 in. wide and 1/2 to 1 1/4 in. high. Cut triangle-shaped blades on top edge. Attach using damp brush. Insert tree; position pumpkin to hide sticks supporting moon.
* Combine Golden Yellow with Lemon Yellow and Orange for yellow shown.
* Combine Leaf Green with Lemon Yellow for green shown.
* Combine Violet with Rose for violet shown.