this dude takes the screen off and on and shows all the different modes, may give you an idea of how much movement the screen has...looks like any typical laptop to me
I type on my lap when I'm in bed at night all the time and it doesn't bother me at all. Now...the weight distribution and ease of dumping it backwards is another story...but that's just the nature of the beast here. I wouldn't want to make the keyboard heavier just to avoid that...
Can't say about all the FB's, but they all can be made to wobble. However, any movement of my clipboard when attached isn't distracting to me. Like everything else, some will be bothered and others won't.