Here's a look at the board in it's off-the-shelf mode of operation:
Access the Innards
The screws that hold the lid on are hidden under the laminated graphic on the lid.
Unscrew these to open the board.
In the base you'll see the controller board, a piezo-electric pickup (used for knock detection), speaker, molded battery box, and the side switch.
Here you can see the very clever linkage that converts the rotation of the motor into the figure eight pattern of the circular magnet.
Prep the Motor
Carefully flip the lid over. The motor is connected to the driver board with two wires. You can snip these with some edge cutters and then trim away a bit of insulation so they can be connected to the motor FeatherWing later.
Pull out the old LEDs - you'll be replacing them with NeoPixels! You can use a bit of isopropyl alcohol to assist in releasing the hot glue bond.
Now you're ready to begin adding in the new electronics.