If you are just replacing the external rm1 cable (from back of robot to controller) then you won't lose anything. I thought you were replacing the cable inside the robot arm that goes to the EE connector.
I don't see why you would disconnect any encoders to do that.
Unplugging a robot from the controller doesn't cause any loss of memory so no need to restore any backups.
Unplugging a robot from the controller won't cause loss of encoder counts either.
If you disconnect an encoder, which I'm not sure why you would, then the robot will lose that encoders position. Once you lose that you cannot send the robot back to a position because it no longer knows where it is. It must the restablish the marker pulse. At that point you must do some sort of mastering such as quick master, single axis master, or zero master.