In advance: Make cookies. Prepare and roll out dough. For each treat, cut 2 ovals using large cutter from set. Cut curve in top of heads, about 1/4 in. deep, using narrow end of cutter. Bake and cool. Outline cookies with tip 3 and full-strength icing; flow in with thinned icing. Let dry overnight.
Decorate and assemble owl using full-strength icing. Using tip 2, outline and fill in 3/4 in. wide scalloped eyes and 1/2 in. long nose; pat smooth with fingertip dipped in cornstarch. Pipe tip 2 eyelashes and tip 3 pull-out horns. Using tip 366, pipe pull-out wings. Attach head; support top with a section of Cake Board to hold level until icing dries.
* Combine Violet with Rose for violet shades shown.