As for the shadow thing. That's something that's always bugged me.
Watch Jedi. The throne room confrontation. When Luke's giving his"I will not fight you father" babble, you can quite clearly see Vader's lighsaber cast a shadow (obviously from the prop he's holding and not intentional). Later on when Luke's just cut off Vader's hand and he's standing over him, there's no shadow from Luke's saber. (again not intentional)
I've always thought that there should be no shadow from a lightsaber.
I suppose if the saber's close to an object there would be a fuzzy type of shadow occurring, but from a distance there would be nothing.
But what do I know, I'm no scientist.