As far as the light, is it staying mounted under the rack, or being moved? No reason to route cables internal to the fork if light is mounted to the rack.

The rack supports may be hollow, but probably not designed for the cable.

Oh, rear light too. Retrofitting for internally routed cable would be a pain.

Maybe you could use the REELIGHT on the rear with no wires.
https://www.reelight.com/en/