okay, wierd, I finally tried this 7 step procedure...twice atually, with the same result:
I sure do end up with all keyframes beyond the (new) first frame removed... but there is still some (but not all, most is gone) movement... very, very strange. IOW, I have appendages moving when there are no keyframes.
Wait, correction: I just checked the graphs and indeed found keyframes in those moving parts, but none showing up in the animation palette. 
whatever, I can deal with this, it's still helpful as most of the movement has indeed been removed.
still...it's weird...more tasty Poser cobbler...