The other day I was recommended /r/prettygirlsuglyfaces for people making expressions that are atypical and not beautified. Pause a movie mid action sequence and you'll also get some like these. My high school had a copy of this book if you have some cash to spend. Good luck! :)
You mean like...a library of people making different expressions? Bodies in Motion has a small one. And I know of at least one book that compiles photos of different people making a variety of expressions. It's called Facial Expressions: A Visual Reference for Artists by Mark Simon.
That's the one, I recommend returning it if possible. Again, start from life. http://www.amazon.com/Facial-Expressions-Visual-Reference-Artists/dp/0823016714
Pastels, no. I've never touched them. I wouldn't worry too much about them, though. Learn to draw, first of all. If you can draw, the world is your canvas and anything you touch is a medium.