Question: When Phoebe is on the phone with Ray, he mentions that the Ghostbusters fire house is now a Starbucks. In the post-credits scene, we see that Winston has purchased the fire house so the Ghostbusters can get back to business, but the fire house looks like it has been abandoned for several years and no other company ever took it over. Did I miss something here?
Answer: Perhaps nobody wanted to take over the place for a few reasons. Historical purpose, high cost... hauntings.?
Answer: It's been 40 years since the Ghostbusters disbanded, Ray mostly likely passed by the old place and saw a Starbucks there. It has since shut down.
But they left the ghost trap active? Not likely.
Question: Is the 1989 Ghostbusters II film still canon or does this film retcon it?
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).
Answer: Ray was probably being sarcastic, and was simply making a general comment about gentrification in the area.