Trust me, I've slow mo'd the hell out of the play. The ref didn't make the call until after the ball was inbounded, so the right call was made.
I don't think it matters when the official blew the whistle. All tht matters is whether the action he was blowing the whistle about happened before the ball was inbounded. There is no time limit on how long an official has to call a foul after something happens.
That said, it's the officials discretion to say whether or not the foul happened before or after the inbound. You can't review the tape to find out, and it was pretty clear the other official thought the first official was crazy for blowing the whistle in the first place, There is no way they were going to say anything other than the foul happened after the inbound after they talked about it. That sort of contact happens all the time at the end of the game, and it never gets called.
Once the whistle was blow, I thought we were in trouble, as most of the contact happened before the inbound, and it takes the official a little time to realize that there is a foul. If he blew the whistle just after the inbound, the foul likely happened before the inbound.
I don't think it changed the outcome of the game, because in almost any other game, the foul never gets called in the first place. Because of the penalty, you basically have to throw someone to the ground to make it a foul before the inbound.