This video is a good example of following up your shot. It also shows the other 2 players in an on-sides position before the 1st shot was kicked. Even though they are past the 2nd-to-last defender during the rebound... it is measured from the time the ball was kicked; and they were behind the ball itself; and they did not end up participating or obstructing the play. So for all those reasons, they were not in an illegal position.
Unfortunately, this goal got taken away because the referee did not recognize this. But that's the way the ball bounces sometimes... the referees are learning as are the kids... Hopefully kids, coaches, parents, (and referees) can learn from watching this great video! Thanks to Dan Robinson's PFC 99 White team for contributing this video!