Great demonstration Pete. It seems to prove that one can't really tell a difference. My "guesses" were no more accurate than random choices would have been. It would be fun to see a spectrograph of each mouthpiece playing a single note at identical dynamic levels.
Your deception on #8 proves beyond a doubt that the concept of the (experienced) player makes far more difference in the sound than the physical attributes of the equipment.
Yes, you'd think if there was an inherent "metal sound" it would still be there when played with subtone.