Then the left arm moves independent of the body during hinge action?

Yes.

The Left Hand moves away from the body from Release to Both Arms Straight, either because the Right Arm is Straightening and/or CF and Pivot Thrust Blast the Left Arm away from the Chest (TSP).

I think that the Idea of "Gluing the Arms to the Chest" is a way to subjugate Arm Motion to a back-seat role while the Pivot controls the Orbit of the Clubhead. It's not so much about the Left Arm. Gluing the Left Arm to the Chest is a way to "Shut Down" the Right Arm. It turns you into a "One Arm Swinger" with one arm swinger tendencies.

Rather than Blasting the Left Arm off the Chest, a player increases Pivot Effort. All neophytes understand effort and for them, more Effort equals more Distance. Adjust your Grip and bend over enough for the Clubhead orbit to intersect the Ball and glue the Left Arm to the chest, then crank it up.

Power Package and Hinge Action is not easier to learn, but it's like learning to ride a bike. Once you learn, you never forget. It works for every club in the bag and on every golf course. And, Power Package and Hinge Action come with a valuable prize. A solid "Downstroke Acceleration Sequence".

It's not the easiest way to learn, but it's the easiest and most rewarding way to play.

That would be when and if the hands move on a steeper plane than the shoulders. With a horizontal hinge and a shoulder turn that is flatter than the inclined plane, the right arm has to straighten to keep up with the chest - as seen from the plane of the "chest turn".

I'm speaking a little hypothetically here; On one side I believe this has to be done to combine a steep hand path with a shallow shoulder turn. On the other side I think it is worthwhile to aim for having all forces running on plane through the impact zone.

I was practicing some bermuda short game today. I have been struggling with that for some time. The prectice was a solid reminder of how important it is to get the forces on the inclined plane through impact. I had to lift my chin and drive my Right knee towards the ball to make that happen. And then I had pretty good control out of some pretty bad bermuda lies.

Yes, and perhaps even slightly towards the right of the chest center since the right hand is below the left on the club shaft.