Obstruction Clarification

[njdevs00cup]

9/10/11 year olds. Runner on first. Batter hits a gapper. As he rounds first base, the first baseman unintentionally bumps into him. He makes it to second w/o a throw and makes no attempt to go to third (runner who occupied first is now on third).

Do I protect the obstructed runner only into 2nd base?

If he is thrown out by 20 ft at second, can he still be called out?

If it is a close out at third (assuming the batter attempted), can he be called safe due to the obstruction between 1B and 2B?

Is the placement of the runners at the discretion of the umpire when the ball becomes dead (ie. the runner stopped running to 2B at the point of obstruction and returned to 1B. Can he be awarded second?)

Thank you for the help!