They'll certainly go with a new adventure using the previous characters, but I'd honestly love it if their roles were cameos or background to some new people in different roles and new issues to overcome, in a new setting. The general vehicle of seeing an actual game from within the world worked well, and plenty to use, but I feel we've seen these characters' arcs and it will feel heavy handed to invent more problems to overcome. And I get it, that's exactly what players will do with their established party, but a lot of the deeper arcs wold be over many adventures and playing sessions, not as a one shot.
But I hope they turn out something decent. I'm all for a lower budget, more character interaction and back and forth.