For the cookies: Add the flour, cookie mix, eggs and butter to a stand mixer with the paddle attachment and mix until well combined, about 3 minutes. Form the dough into a disc, cover in plastic wrap and place in the freezer for 15 minutes.
Preheat the oven to 375 degrees F. Line 2 baking sheets with parchment.
Cut the dough in half and roll to about 1/4 inch thick, dusting with flour as you roll. Use the outline of a double-drama mask cutter to cut out as many cookies as you can and place on the prepared baking sheets. Repeat with the remaining piece of dough. Reroll the scraps to get about 24 cookies. Place back in the freezer to chill for 5 minutes.
Bake for 8 minutes (or according to the package instructions). Cool completely on wire racks.
For the decorations: Stir together the confectioners' sugar and half-and-half in a small bowl to make a smooth, thick glaze. Transfer half of the glaze to a second small bowl and add the black gel coloring.
Knead the white modeling chocolate and roll between parchment paper as thin as you can (about 1/4 inch or less). Do the same with the black modeling chocolate. Brush the surface lightly with powdered sugar if it seems like it's beginning to stick.
Use the sad drama face cutter to cut 24 faces (or as many cookies as you have) out of the black chocolate, dipping the cutter in powdered sugar in-between if it sticks. Use the flat end of a skewer to release gently from the cutter. Use the smiling face cutter to cut 24 faces (or as many cookies as you have) from the white chocolate. Spoon the left sides of the cookies with the white confectioners' sugar glaze (adding a little more half-and-half if it gets too thick), leaving a border around the edge. Affix the black masks on top. Repeat with the black glaze and white masks. Let the glaze harden before serving, about 30 minutes.
If the modeling chocolate is too firm to roll, microwave for 5 seconds, then knead in your hands until pliable.