It might be hard to wire in a neutral safety switch on your AD, although a clutch pedal switch could be used (closed when the clutch pedal is fully depressed.) But either one of those only work on a solenoid operated starter. If you have a stomp starter then all bets are off on wiring one in.
Modern vehicles use these to prevent idiot drivers from starting a car in gear, along with other features like lane departure, blind spot warning, etc. to protect the rest of us from incompetent drivers.
I think it'd be OK to leave those wires out.
