1) Well it's the eternal question isn't it? Would he have still done all he did without the interference of the wiches? Like in the matrix, if she'd not said the vase was there, would he still have dropped it? That's why I think they start the play.
2) Demonstration of power perhaps. Plus the sexual aspect.
3) I don't know. I think they are a little but they're big tough warriors and probably think that all the magic in the world won't help them if they get their heads cut off. The placement of women in society at the time, regardless of withces could have something to do with. However the newws they're giving isn't threatening either so more reason to be curious than afraid.
4) She's an ambitious lady with a keen eye for social standing and she wants power. She's not exatly the warm hearted female type.