The aircraft will carry out an autoland from an ILS approach unless the pilot presses the disconnect button - and it won't give a damn about legalities or the number of lights seen. If the runway won't be in sight at Cat 1 minima, then how are you going to ditch when the sea only comes into view a few seconds before impact? Option 1 is the only sensible one -hopefully all will take this incident on board and take into consideration Perth's isolation (and other airfields around the world) when fuel-planning.