Combine 2 packets primary yellow fondant with 1/2 packet orange; roll out 1/8 in. thick. Using pattern traced onto parchment paper and back of knife, cut out yellow-orange tree/moon.
Roll out 2 packets orange and 1 packet each violet and black fondant 1/8 in. thick. Using pattern traced onto parchment paper and back of knife, cut out violet owl body, pumpkin mouth, pupils and nose and black owl wings and beak. Cut orange pumpkin with cutter. Set all on cornstarch-dusted cake board to dry.
Cut orange fondant tree; attach over yellow base using fondant or gum paste adhesive. Let dry completely. Roll out small amount of white fondant 1/8 in. thick; cut pumpkin and owl eyes. Let dry completely, at least several days, on cornstarch-dusted cake board. Reserve unused fondant
Attach owl fondant pieces to tree branch using adhesive; let dry completely. Roll out reserved orange and yellow/orange fondant 1/8 in. thick; cut 1 pumpkin shape from each. Cut pumpkins into thin strips and attach to dried pumpkin plaque with adhesive; add facial features. Let dry.
With FoodWriter, add owl eyelashes. Attach lollipop sticks to back of tree and pumpkin plaques with adhesive. Let dry.
Bake and cool completely your favorite 2-layer 10 in. round cake. Stack cooled cake layers on foil-wrapped 12 in. cake circle. Prepare cake for fondant by lightly icing with buttercream.
Knead together 3 packets Primary Green fondant with 12 oz. white fondant. Roll out 1/8 in. thick; cover cake with fondant. Roll out orange fondant 1/8 in. thick; cut 32 in. x height of cake strip; attach around cake using damp brush. Roll out white fondant 1/8 in. thick; using narrow end of tip 12, cut white dots (300 used on project pictured) and attach to orange fondant in staggered rows using damp brush.
Re-roll remaining green fondant to 1/4 in. thick. Use pumpkin cutter to cut stem and medium leaf Cut-Out for pumpkin leaf; attach to pumpkin with damp brush. Cut thin fondant strips for stem and leaf details; attach with damp brush. Attach leaf and stem to plaque. Cut 18 assorted strips, 1 in. to 4 in. long x 1/2 to 1-1/2 in. high. Cut triangle-shaped blades along top edge. Attach to top of cake with damp brush. Insert tree and pumpkin plaques into cake.