I still belive the surprise is the Star Trek Phase II footage. There is aRobert Meyer Burnett tweet from the 26th of September that says:
The dude in this STAR TREK PHASE II footage is totally wearing a LOGAN'S RUN costume. #TNGS2
I clearly remember that the day after the post somebody asked that where will we see this, and he said on December the 4th, although I don't find that comment right now (maybe it was deleted, to keep the surprise, but you can see the #TNGS2 tag anyhow on the initial post). So it seams that there was some Phase II footage (probably test footage), and now it will be incorporated as an extra, and I really think it is a logical choice, as the premier episode of season 2 is based on a Phase II script, changing the characters (it should have been Ilia getting pregnant on Phase II), so the connection to Phase II of Season 2 of TNG is evident.