Visible crew/equipment: When Trevor is uncovering the ECTO-1, you can see the camera's shadow on the left of screen and even briefly on the car front.
Visible crew/equipment: When Gary opens the trap next to the 2 school buses, he is wearing a cable attached to an earpiece on the right side of his head. The kind of cable actors wear to receive instructions from the crew. There's no reason plot-wise for him to be wearing it (he isn't receiving any instructions from the kids, who are right next to him).
Answer: Yes, it is still canon. Director Jason Reitman has confirmed it is, and there are actually lots of easter eggs referencing it in "Afterlife." For example, Ray still has his bookstore from "Ghostbusters II." The "dancing toaster" is in the farmhouse. Etc. They chose not to directly reference it in dialogue since it didn't have much to do with the plot, but there are plenty of hidden details confirming it is still canon. Reitman has also said that there are plans to possibly bring back more plot/characters from "Ghostbusters II" in the future. (It just depends on what direction the sequel ends up going in).
TedStixon