Deliberate mistake: When the kids are about to jump start the trap Phoebe hides behind the school bus door. Half a second later, when the trap opens, she's nowhere to be seen, not even jumping or stepping inside the bus. Then half a second later she has managed to get inside, turn around and protect her head while the bus windows burst. It all happens in real time for their hairs are still fluttering. It sure paces up the scene, but it's really awkward.
Deliberate mistake: The mother jumped through the window, shattering the glass, but did not get cut or tear her clothes. (01:28:55 - 01:31:10)
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