I transitioned out of the S-3 last Nov and hope that the press got this one wrong and two of my buddies are still alive, but I fear the worst. My prayers are with them.
As for the seats, when armed and in group, any front seat handle will eject all 4 seats occupied or not. There is no turning off the rear seats. The aircraft is always flown in the group eject mode so either of the front seat crew can eject all onboard. When strapping in/out, the seats are in the single mode which means a pulled handle on an armed seat will eject that seat only (this is the only mode for the rear 2 seats).
As for the seats, when armed and in group, any front seat handle will eject all 4 seats occupied or not. There is no turning off the rear seats. The aircraft is always flown in the group eject mode so either of the front seat crew can eject all onboard. When strapping in/out, the seats are in the single mode which means a pulled handle on an armed seat will eject that seat only (this is the only mode for the rear 2 seats).