While the original cast doesn’t appear in the new Ghostbusters: Afterlife trailer, there are tons of references to the elder Reitman’s film.
I mean, you probably would be too if your dad was Ivan Reitman, the guy who directed the original series.
We hear audio from the old movies, we see props from the old movies, and there’s even a reference to a character who was discussed but never seen in Ghostbusters who almost certainly factors into the new film’s plot in a major way.
It’s pretty clear from the Ghostbusters: Afterlife trailer that Jason Reitman is a big fan of the original Ghostbusters.