Regarding the "immaculate ejection"...
It's as good of a guess as any. When he hit the water his cru-69 (whatever) was disconnected from his harness and they never could recover the seat or the plane. He was in a defensive breakturn and that is a violent, aggressive maneuver. At 9 G's his neck is supporting around 200 lbs so not noticing a 40 lb pull on the face isn't unreasonable.
I highly doubt the pilot actually did anything to cause the ejection. In a breakturn the only thing being PULLED is the control stick. Everything else is a PUSH - feet on the pedals, calves, legs, butt muscles all tight, left hand on the throttle or pushing on the canopy rail, etc. Nobody I've talked to can figure out how a guy in a breakturn could pull the handles unless part of his gear was hanging loose and got caught in the handgrips.
That all assumes the seat and associated equipment was functioning properly. No pilot worth a crap is going to point at egress and say "your seat punched him out by itself!", even though that is something that theoretically could have happened. The T-37 -1 has a warning about putting stuff under the seat because if the seat slams down to the floor hard enough and hits something under the seat, it could theoretically fire. There was a landing mishap where a T-38 hit a barrier and the force and angle of the collision fired the seat killing the pilot. It's possible that during the breakturn the seat lowered suddenly and something caught the handles or something else on the seat, and it fired.
I guess my point is that we can't prove what happened, and we can be equally confident that the pilot didn't just pull the handles and the seat didn't just decide to fire itself for no reason. That leaves only a few possibilities, and the only bit of personal equipment that can physically reach the handles and pull them is the O2 hose if the cru-69 (whatever) gets disconnected from the harness. Nothing else really seems to be possible or make any sense.
Now I've heard of F-16 pilots punching themselves out while taking a piss inflight, but the one I remember involved the G-suit at the knees getting hung up on the control stick and the plane going out of control, not anything getting caught on the handles and pulling them. I usually safe the seat before loosening the straps and moving around in the cockpit but that's a personal choice I make.