Once you're sure everything's working, seal up all the electronics to keep water and dust out.

Use hot glue and 3/4" clear heat shrink to seal both ends of all your LED strips. 

Use 1" heat shrink and/or self-sealing silicone tape to enclose the Feather and hall effect sensor together into a little plastic-coated bundle, with the two JST connectors sticking out the end. Fill that end of the heat shrink bundle with a little more hot glue. Seal it up as much as you can while still keeping the USB port accessible. 

Select three spokes that are placed at equidistant angles around the wheel. Use zip ties and clear silicone self-sealing tape to secure the three pairs of strips back-to-back along the spokes, in the order shown and matching colors in the back-to-back placement.

Manage the wires around the hub of the wheel with more zip ties. If these wires catch on the gear mechanism or get out of line in any way, they'll very likely break. Spend a little time doing some wire management for safety.

Use some strong zip ties to secure the controller to the battery, and the battery to two spokes. Tighten the zip tie just below a spot where the spokes cross, so the centrifugal force pulling the battery out toward the rim of the wheel as you ride pulls the zip tie against the widening spokes and keeps the battery firmly in place.

Make sure you can reach the USB ports and the on/off switch on the battery easily.

If you're taking this to a dusty, muddy desert, add self-sealing silicone tape around the USB port connection to seal it up once you're done testing.

Use 5 minute epoxy or another strong adhesive to glue the rare earth magnet to the inside of the frame, at the location where the magnet sensor will pass directly by it as the wheel turns.