1) Legal as long as he touches all of the bases before he crosses home plate.
2) It depends... If the kid asks for time then ties his shoe then he is safe, but if he doesn't say anything to the field umpire then he is out.
3) If the runners cross home plate before he is ruled out then they count... It's the same scenario as hitting a double with someone on second and them scoring, but you try to stretch to a triple and get thrown out long after the runner has scored.
4) Runner gets second base and umpire hears a lot of booing.
5) Hopefully the sun is all we see.