1. I probably wouldn't have called it in this 19 second vacuum, much less have a word with #8. Only way I am calling it is if the temperature of the game is high and/or I've noticed incidents with that offending player earlier. The bench/parents were the only ones that really reacted to the contact. #7 himself, the one that was bumped, seemed to care very little about the contact. If I am at all worried about the impact that this little moment would have on the game, I would probably just say something semi-privately to #7 at the next stoppage along the lines of: "I guess he didn't like that you did him dirty like that, huh?". Better if one other of his teammates overhears it as well. That's my personal style though.
Caveat: same type of contact in an older girls game, I will call it. Boys and girls play the game entirely differently, have completely different views on in-game justice, and girls are not likely to respond positively to the tactic I used above. Call me sexist, but thousands of games of experience have taught me that if you try to ref both boys and girls the same way, you are going to have a bad time.
2. Common sense dictates that a referee wait no more that 2 seconds to see if a play develops to call advantage or call the foul. Anything longer and it may seem weird. BUUUUUUUUT... that is just a general guideline. Assuming there was a foul (ignoring point #1 for this thought experiment), I thought it was an appropriate amount of time to call the foul. The "foul happened, he passed it to a teammate, and the referee waited just long enough to see if that teammate would gain an advantage, pass it backwards, … or kick it lamely out of bounds. You don't want to be calling the foul right as an attacker breaks past the defense toward goal.
To go even further into advantage and how long to wait. I didn't mind the length of time to call the foul, but... because the dribble made by 22 was so pathetic, I wouldn't have awarded the foul. However, if he controlled it and passed it backward, I would have called the foul. #22's mistake was completely unrelated to the foul, so I wouldn't give a foul after an advantage ended in that manner. If a teammate or coach says "but there was no advantage" I would say, "Yes there was, but then he squandered the advantage". Basically, the unwritten rule is: if you wait that long for your whistle, you don't reward a poor play; but you can call a slow foul after a neutral play.
Whether or not you use a slow or fast whistle is dependent on a combination of personal style and temperature of the game.
