Flip cards say jettison drop tanks unless they are empty. But I suspect that the jettison facility in not cleared for use now.
Both the landing gear and the hook are powered by the green hydraulic system. Emergency power for both is provided by the red system. But as the use of arrester gear with landing gear up is not permitted, all of this is rather academic.
Perhaps the most curious aspect of this incident is the fact that the Ram Air Turbine (RAT) was deployed. This powers only the blue system, which operates the flying controls. So the use of the RAT could not do anything to help get the gear down.