Maybe some Star Wars fanatics can fill me in...

I'm a casual fan of the original trilogy, but by no means a Star Wars expert. I played this game, it was fair, however I thought the story was a little lacklustre and familiar in parts, but it got me thinking about something.

Seeing as there is so much Star Wars product (cartoons, video games, etc.) with their own stories, does each one have to be given the nod by Lucas himself? I assume he didn't write The Force Unleashed but would people come to him with the synopsis and he says yay or nay?

Furthermore, I see on these boards many people referring to this game as canon. Are there therefore non-canon story lines in some games that people don't consider actually occurred in the SW universe/mythology?

The reason I ask is because this game (to me) seems to change my views quite a bit of various things in the films. Maybe I'm wrong here but isn't it insinuating that the rebel alliance was actually formed because of Vader's shadow cell (i.e. Starkiller)? And I must say I do feel Vader and the Emperor should have seen all this stuff with Luke coming as it happened virtually exactly the same with Starkiller in the end scene. It just makes me feel that in ROTJ those two should have been saying "This seems familiar".