I know exactly how replay works. I don't think you understand how it works. The refs will have 1 of 3 announcements. It's either "the ruling is overturned", " the ruling on the field stands", or "the ruling is confirmed". "Overturned" means they were wrong. "Confirmed" means they were right.
"The play stands" means they don't have enough evidence, so go with the call on the field that was made by a dude from 20 yards away. The commentator literally pointed out that the ref said "stands" not "confirmed". You can piece all the cameras together, use ipads, iphones, etc and still not get the proper view, even when you sync them. That's why he said the play "STANDS". If the ref saw something on all your cameras like you say, he would've said the play was "CONFIRMED". None of the 4 monitors you talking about tells us anything. You can see the ball but you can't see his knee or line to gain from the End zone view. From the upper view you can see him dive but you can't see when his knee touches the ground and you can't see the ball. All we know for sure is he 6'6 and his entire torso is across the 40.