Spirit System

I know the GeoLink needs to be away from magnetic fields to allow it to function correcty .

How about the connecting Cable , is it influenced in the same way or more robust ?
What would the closest the Cable could be safely run past something like a Motor or Servo ?

The cable can be much closer to the motor/servos.
3 cm distance or more should be fine.
Motor and ESC could induce a noise in these cables same as it will happen for BEC cables. But GeoLink has built-in voltage filters so it should be fine.