moving screen

[Starman311]

Sorry for bumping this again, but it appeared no one was really addressing my questions in the previous reply. I'm wondering if a screen/roll is illegal when:

(1) screener is moving but in the same direction as the offensive player he's attempting to screen (no or minimal contact is made)

(2) screener rolls into the path of the offensive player he's attempting to screen "just" before contact is made thereby activating what might be termed a "back screen"

(3) A1 dribbles to a spot (e.g., elbow), picks up the ball, performs a legal pivot, and creates a "back screen" for A2 rubbing past his screen. B2 significantly contacts A1 by running into his back causing A1 to move his pivot foot.

Thanks for your help on these.