Your bar placement looks about right. There's a little shelf that develops between your scapular spine and the posterior deltoid when you get the bar on your back. That's where it will be most stable. Do you have the book? It is addressed in there.
Squat looks pretty good, but you still have the forward knee travel at the bottom. The knees need to stay in place from halfway down to halfway up. You need to stay solid at the bottom and continue to sit back before the ascent. Fix that and you are golden.
From what I could tell on power cleans, you look okay. However, the videos are shot so that it is difficult to see what is going on, so I may be missing something.