He claims none of that ending was actually shot, but that seems to be at odds with the trailer shots of Jyn running around the Imperial base and beach with the plans in hand.
Fascinating. Why do you say that Jyn running around the beach with the plans in hand implies they shot an ending where she survived? As far as I can figure, her survival would only affect what happens after she transmits the plans - and the scenes running around on the beach with the plans took place in between getting the plans from the Archive and transmitting them at the Tower (originally separate structures), which has nothing to do with surviving post-transmission.