Coach, in the first scenario, you got different answers because you didn't give us the entire series of events. That left open the possibility of different rulings.
In the first play, since the official indicated 1 shot, there's no official's mistake. When he blows the whistle, B has the ball. B should keep the ball. They should not have gone to the arrow.
In the second play, by rule, it's a technical foul. If the kid simply forgot he was in the game and ran out 5 seconds late, I probably wouldn't call the T. However, if he ran onto the floor at his end and got a cheap basket, yes, I would certainly throw the T.
Your questions are always welcome. I check out your board from time to time, just to see what the other side is saying.
Keep up the good work.