Well, I would say that there are lot's of people capable of demonstrating these things. I've offered to do that myself, but I don't see many criteria being presented to look at.
Sigman's teacher test is a good start...and it's basic...being able to ground a decent push without locking up your shoulder, in other words, with a pretty relaxed frame, is also basic. And we haven't even gotten to seeing whether one's Dantien drives one's movement, a key req for internal arts.
And there aren't lots of people demonstrating these things. There just aren't.