So our friend Alex Billingsly of FirstShowing.net says...
They've hidden multiple secret endings at the end of credits on different prints, and you have to go to different theaters to see them.
Fox is a bit desperate to try and get people in theaters on May 1st for the opening and this definitely seems like a very unique decision to try and bring people in. While we've seen plenty of easter egg endings, like on Iron Man last year, we haven't seen multiple endings like this in a long time. Hood didn't specifically mention how many different endings there were. As for the other differences between the leaked version and the final cut, Hood explained that there were 400 unfinished visual effects shots and that there was no score, unfinished sound mixing, and unfinished color timing. However, he didn't mention anything about differences in actual footage.