Wrap the NeoPixel strip around the inside of the cauldron's rim, and secure it with more tape if needed.
You can place all of the parts inside the cauldron, and use gaffers tape or double stick foam tape to secure things. It's also OK to leave things loose in there if you like.
Cover the circuit and speakers with some black tissue paper or fabric
Secure the IR sensor to the side of the bowl's rim, pointing in toward the sensor. You can adjust until you feel the placement is best, then tape the sensor to the inside.
You can also diffuse the lighting a bit with some tissue paper if you like.
Time to fill the bowl with candy. You're ready to give out some scary (and delicious) surprises!!