Ian W
What if the autopilot is also disabled. Very likely with O2 bottle fragments flying around the E/E bay causing power interruptions.
Once trimmed for cruise and with bank angle protection(30degs) the 777 will fly on to fuel exhaustion on a random route. As for flying over any waypoints- probably just by chance. Flying an airway- I've haven't seen any accurate centreline radar tracks.
As for exceeding vmo-as trimmed fo cruise with both engines going, once the engines flame out, it'll pitch down exceeding VMO.