Weird Play -- FGCU/Lipscomb

[DadofTwins]

A41 inbounds to A5, who catches the ball above his head near halfcourt. B23 guarding closely, leaning toward the slightly-taller A5. A5 turns, with the ball still above his head, to face B23. B23 collapses in a heap. Official facing the play calls nothing. A5 takes three dribbles, B23 does not get up.

Baseline official whistles, and the two officials (the one who blew the whistle and the one who was nearest to the play) go to the monitor. B23 gets up, rubbing his throat.

The call is Flagrant 1 on A5 (elbow above the shoulders), B gets two shots and ball.

3 questions:

1) If the calling official has nothing from 2 feet away, can/should a partner overrule, especially from distance?

2) If no foul has been called (or if the contact is ruled "incidental" during the play), can the officials go to the monitor and assess something after the fact?

3) In general, if a player intentionally puts his head in harm's way, is the foul still the responsibility of the player with the moving elbow? If so, why? (I'm a soccer guy, so I'm used to holding the player who creates the dangerous situation responsible for the resulting action).

Thanks in advance.