I know of a newly minted 1500 guy who just got a yes and I’m sure he is going to do well. And you do not have to have the the written done prior to interview, it just has to be done prior to Indoc.
Good luck! I’ve been told by multiple people that should you get the invite to an Expo, carry some confidence in that you have an offer coming your way and that they’re serious about you. I was also told by a current FO while I was up in TEB before, that if it does not work out the first time, and you still want it, to wait for the window to open up again, and go at it again, and that he was proof of that.