Yes, it is coach's interference if, in the judgment of the umpire, the base coach at 3rd base, or at 1st base, by touching or holding the runner, physically assists him in returning to or leaving first or third base.
The base runner can not advance on a foul ball, he must return to the base he was at before the foul ball was hit. A base runner may advance on a caught foul ball, but must tag up and advance only after the ball is touched by a defensive player. To answer your original question, yes, all base runners must return to the base they occupied prior to the foul, and must touch that base before play is continued.
Yes
As long as the coach does not assist the runner, there is no penalty.
If it is a force (i.e. there are people on all the bases behind the runner) play, then yes, the baseman needs to touch the base to get the runner out. If the runner is not required to move to that base, then the baseman must tag the runner to get him out. The baseman does not NEED to touch the base to record the out. The defense may tag the runner OR the bag.
The 1st base coach can never be out of the coach's box. The 3rd base coach can only be out of his box when the ball is hit and there is a runner on or advancing to 3rd base.
If the runner gets tagged, then he is out. If the base doesn't get stepped on or the runner gets tagged, then he is safe.
Yes. He must tag the base.
The pitchers mound
No. To force an out, the defensive player has to touch the runner with the ball or touch the runner with the glove while the ball is in the glove. A thrown ball touching a runner does not count.
No. You can't even touch a base out of order. If you pass a runner (and touch the next base before he does) you are out.
an out