Re: "stance of heaven (and earth)" and IS
There's plenty of video of my teacher available. You can decide for yourself whether he looks immobile.
A DVD set from Gleason Sensei's recent seminar at Aikido Eastside will be available soon. It was filmed just a few days before the post you responded to, and probably includes his discussion of this very issue.
As for "unraveling the mystery," that's easy. Quit trying to dissect message board posts and get some mat time with the people you're trying to understand.