The pedal steering is limited to 7 degrees. It does begin immidiately upon displacing the pedals but with the large pedal movement needed to attain the relatively small 7 degree displacement it seems to be delayed or lagging.
Inserting the steering bypass pin has nothing to do with anything in the rudder system. It merely causes the hydraulic fluid that would be displacing the steering collar to be bypassed and circulated in the system without ever getting to the steering actuators.
As for
"backdrive the rudder pedals through the cable system and not move everything attached to the rudder pedals"
everything attached to the rudder pedals DOES move.
It isn't really all that complicated. Honest. Really, You can believe me...