AP throw ins

[letemplay]

Need a refresher(s) on arrow changing or not:
All plays are with Team A having an AP throw in:
(1) Throw in that leaves thrower hand and comes inbounds, touched by several players, but is never in possession by either team and another held ball is called. Arrow is changed and now should be B's throw in?
(2) Throw in is air mailed across court without hitting any player.
(3) While attempting the throw in, A1 steps across the line and is whistled for a violation.
(4)Prior to throw in coming inbounds, B2 fouls A2

Which situations call for arrow to change? Pretty sure I know these but would like to see a response(s) Thanks.