There is a possibility of a Artoo/Threepio cameo… even a Leia cameo right at the very end of the piece.
I am reminded of the Skyhook sequence in the Radio drama.
You may get the glimpse of a white robe and a few out of focus droids as the contents of the tapes are transmitted ship to ship.
I can’t remember if I said it here, but my vision of the Vader cameo in Rogue One was just a shot at the very end of the film of Vader’s back as he stands on the bridge of his Star Destroyer bearing down on the Tantive IV before we smash cut to black.
I was pretty close with the tease in this trailer, but with Vader on the Death Star. I imagine he’ll have a bit of a larger role at this point.