I do not see that wire in particular preventing the starter from turning while in reverse. Now if the connection where that same wire goes from the start relay to connector just before the reverse module is open, yes, no spinny. Doesn't explain your measured open condition though.
Regardless, have you checked all the interlocks? Clutch switch open? I believe a clutch switch stuck closed would only show up while trying to engage cruise, reversing or able to start in gear.
Since the neutral indicator gets its signal from the reverse module you should be good there if showing green. If your reverse light comes on, the reverse switch is good.
So, yep, I'd guess if all visual indicators are good, verify clutch switch open, a good ring from the ground side of start relay to who knows what pin on the reverse module (sorry no help there
) If there are no breaks in the power to the starter from the relay, I might be worried about the reverser module.
I don't believe the speed sensor will fail in such a way as to not allow any reverse, but this can be verified by disconnecting the connector for the speed sensor on the right rail. The reverser will back a few feet and stop with the sensor out of the system.
Good luck, and JZ will probably be able to help soon.