Bake cookies. You will need one of each shape for each treat. Prepare dough and roll out to 3/16 in. thick. Cut one circle using second smallest cutter and one circle using the second smallest (3 1/4 in.) cutter from set for each treat.
Invert pops pan and spray with vegetable pan spray. Drape smaller circle over every other pan cavity, pressing to smooth surface. Bake 10-14 minutes, or until firm and golden brown. Cool pan on cooling grid 10 minutes. Carefully loosen bottom edges of treat using spatula.
Place larger circles flat on ungreased cookie sheet. Bake 11-14 minutes or until golden brown. Cool on sheet 2 minutes; remove to cooling grid to cool completely.
Fill treats. Fill one shaped cookie with unwrapped mints.
Make piñata treats. Prepare royal icing. Tint green. Use tip 18 and green icing to pipe a line around rim of candy-filled cookie; attach base cookie. Turn treat right side up.
Decorate tree. Use tip 18 and green icing to pipe pull-out stars. Add yellow star sprinkle to top. Use icing to attach nonpareils.