Re: #2, My understanding of the experiment is that they simply had people assume poses, and then measured their hormone levels. If they really did tell them up front whether the pose was intended to make them feel powerful, that would certainly be an egregious mistake in the methodology, but that wasn't the impression I had from hearing the TED talk.

Actually, I wonder if you could even pull of that version of the experiment without the participants seeing through it ("No really, shrinking into your chair and looking at the floor is a great display of power!").