Mechanics/Ruling Question

[Suudy]

First, I'm not a baseball official. But I've been a football official for a decade, and I'm seriously considering getting involved. I've been lurking here quite a bit trying to grasp a few things about obstruction and interference. To that end, I have a question about mechanics on these situations.

(I presume R1, R2, etc are the first runner, second runner, etc, regardless of base. Or do the numbers denote the base? Also, F1=pitcher, F2=catcher, etc. Am I right?)

First case. Runner on first, no outs. The infield is up for a bunt situation. The batter bunts a fair ball down the third base line. F5 charges in and gloves the ball. During the bunt, the second baseman obstructs R1. The throw to first by the F5 is over the head of the F3 and goes up the first base line (not into the dugout). R1 seeing the overthrow continues and tries to score. F9, after coming up, fields the ball and throws home well before R1 arrives and R1 is tagged by F2 before scoring. What's the call on this? The obstruction is ignored? Is R1 entitled to 2nd base, and any attempt to advance beyond that is at his own peril?

Second case. Same setup. Instead, R1 stop at 3rd. However, the batter, seeing the overthrow, tries to run to 2nd. The throw by F9 is in time to tag the batter at 2nd. The batter is out and R1 is safe? The obstruction is ignored?

Third case. Runners on 2nd and 3rd, no outs. R2 has a big lead off of 2nd. The batter hits a slow ground ball toward F6. R2 pushes F6, interfering with the play. R1 scores on the play. The batter is safe at first. I presume R2 is out. Does R1 return to the 3rd? Is the batter still safe at first?

For each of these, what are the mechanics? How do you indicate the obstruction or interference? In the case of interference, is the runner out immediately? (Edit: I was just reading some other threads, and in some cases the ball it seems the ball is dead immediately. Is that the case in any of these situations?)