Still searching for a teacher? Hmm. Maybe it would be nice to discuss interpretation with someone knowledgeable or perhaps an external guide on my posture but...
So you don't see repose here?

You posted this weak photo in another thread and it still has not improved. It demonstrates nothing but how to sit with your hands on your lap and stay there like a statue. It demonstrates nothing to do with piano playing as piano playing is not a stagnant position and piano is not played on your lap.
No good piano teacher would EVER teach their student to sit as flat as you do in this photo, lets ignore your head and shoulder as you believe you are a grandmaster expert in that field.
Your ass is suffocating that chair, you need to sit closer to the edge, this is a fundamental beginners seating position at the piano and you have ignored it completely.
I would agree with you that keyboardclass can't demonstrate that--- I think he has done enough work to have an intellectual understanding of certain concepts, but hasn't gone very far in the implementation of it, plus is burdened by an aversion to certain subjective experiences. But there are teachers who have gone far with this idea.
I think you have given keyboardclass enough respect and patience with your questions, I am also yet to find a response from him which answers any of your questions. He answer question with questions in an effort maybe to conceal his musical ideology but for me as a musical educator his questions do not provoke any interesting ideas or concepts, perhaps they do outside of piano playing but then as I said before this thread should have been in the anything but piano, because keyboardclass still has not demonstrated how anything about his posture improve or aids piano. I have come across some people on pianostreet who also avoid questions, I simply ask the same question over and over again, if you start to follow their mad question lines and let them avoid your questioning you just end up with a thread like this where nothing is answered and stupid question are just thrown randomly around the place with no context.
If your pattern of breathing adds a tension load to your movement, then I think breathing will affect all activity, piano included.
Yes, but my point was that the improvement that it causes is very small compared to changes made to your pianistic approach directly. It is an indirect improvement, so too would losing some weight or eating the correct food, but it is not a commanding issue, just as considering your head and shoulders is looking at piano the wrong way around if you hope that from there you learn to develop your technique.