For the animal cookies: In a stand mixer with the paddle, cream together the butter and sugar until just combined; do not incorporate air. Add the egg, lemon juice, vanilla extract and salt and beat to incorporate. Add the flour and mix to form a dryish dough. Turn out onto a piece of plastic wrap and smush the dough together, then flatten into a disc. Wrap tightly and refrigerate for 20 to 30 minutes or until you are ready to roll it out.
Preheat the oven to 350 degrees F. Line a baking sheet with parchment paper.
Roll out the dough on a lightly floured countertop to about 1/4-inch thick. Cut out cookies with your cutter of choice and place on the lined baking sheet. (They will not spread, so you can put them fairly close together.)
Bake for 12 minutes, rotating halfway through. They should not really take on any color, just a little bit on the bottom. Let cool completely on the baking sheet.
For the icing and decorating: Place the melting wafers in 2 double boilers and gently stir to melt. Drop in each cookie into one of the icings, top-down. Flip over and remove with a fork. Tap off excess and place on parchment paper. Sprinkle with sprinkles immediately, then allow to set at room temperature, about 1 hour.
Store in an airtight container at room temperature until you have eaten them all.