Crumble the cooled cake and dump it into the mixing bowl. Add 1 cup of the buttercream to the bowl and mix on low to medium until it comes to a smooth texture. Add slightly more buttercream if the mixture is too dry.
Press the cake mixture into the pumpkin and ghost silicone molds. If your mold has a spot for a popsicle stick, insert it as well. Smooth the top of the cake so that your cake pop will have a smooth texture.
Place the filled molds in the freezer for 15 minutes to allow them to set.
Remove the cake pops from the freezer and remove each one from the molds.
Place the orange and white candy melts in separate microwave-safe bowls and microwave them in 30-second bursts, stirring between sessions, until smooth. Dip the pumpkin cake pops in the orange and dip the ghosts in the white.
After dipping, let the excess drip from the cake pop. If you have a cake pop stand, set them into the candy melts harden. Otherwise, lay the dipped cake pops on a cookie sheet lined with parchment paper.
Make the icing while the cake pops set. You can also place the cake pops in the fridge for 10-20 minutes so they set quickly.