Passing runner

[greymule]

OBR. R1 on 3B, R2 on 2B. Batter hits a very high blast down the LF line. R1 takes three steps toward home and then stops and turns to watch the ball. R2 can see that the ball will clear the fence easily, so he runs. R2 rounds 3B and passes R1 (a) before the ball passes the pole on the foul side, (b) after the ball passes the pole on the foul side but before it hits in the stands.

In either case, is R2 out for passing R1?

If R2 would be out in (b), what if the umpire had yelled "Foul" immediately after the ball passed the pole on the foul side, and then R2 passed R1 before it hit in the stands?

I have a game next weekend and fear that this might happen and I won't know what to call.