You don't want to prevent movement of the servo, you want it to imitate the movement from when it had the exhaust valve still hooked up.
As for removing the servo, I am not sure on that. There are only 3 pin-outs on the ECU that are related to the servo. 2 are for actuating the servo motor and one is the sensor for the motor. I don't know if just removing the servo will prevent to FI light from coming on as the ECU would still be looking for it.