> Since it was likely on autopilot

Why do you think that's likely? Because it was a long flight (to wherever it crashed), and pilots tend to use autopilot on long flights? Or is there some other reason?

Would the pilot be able to breathe at the altitude he was flying at? I presume he wouldn't have enough emergency oxygen for the entire time it takes to get to the presumed crash area.

Given the debris that has washed up on various coastlines, would you assume it was a soft landing or hard crash?

What's your take on theory that the plane had a fire and the pilot maneuvered the plane to a high altitude to snuff out the fire, then away from populated areas, then he himself passed away and the plane drifted on its deep ocean course until it crashed?