Since they're carbed, the wiring on these bikes is pretty simple.
https://www.ninjette.org/forums/showthread.php?t=35999
Lights would be the big thing to remove. You could remove the brake light switches too, once the lights are gone.
Other than the clutch safety switch, the left control doesn't really have anything needed on a track bike. A lot of people remove the sidestand, so its safety switch can be wired closed (i.e. just grounding that pin at the junction box and removing all the wiring).
I think you can (could?) buy a PnP adapter to remove the keyswitch and just use the killswitch as the sole on/off.
Beyond that, it's basically just ignition, cooling, and gauge wiring left.