One of the main premises here and at IDW is that the timeline of the movies and the videogame does not mesh with the timeline of the RGB and EGB cartoons. IDW has further exacerbated this by demonstrating that they contain very different versions of the same characters, and they've met on several occasions.
They also showed that nearly every other form of Ghostbusters media, including parodies of the Ghostbusters, have their own timelines in other dimensions, so while the Extremew Ghostbusters believe the Real Ghostbusters are from their past, they are actually from parallel realities (though the future of the Real Ghostbusters does canonically contain at least Kylie Griffin, if not all of the EGB and their cases).
I have taken Dimension 50-S, the home of GHOSTBUSTERS: SANCTUM OF SLIME and run the numbers on what we know for sure DIDN'T happen there. Turns out, the first two movies and the 2009 videogame definitely did happen, as well as the 2011 SANCTUM OF SLIME videogame, and mention is made in comics that at least some elements of the Real Ghostbusters and Extreme Ghostbusters took place here.
Since details are scarce for this world, I went with an all-inclusive model, bringing in everything I could justify. The Cryptozoic Ghostbusters board game made no distinction between the Ghostbusters and the Real Ghostbusters, as spirits from the IDW comics as well as the cartoons were said to have escaped the Ghostbusters' containment unit. The second game differentiates between the Ghostbusters, Real Ghostbusters, and Extreme Ghostbusters, and that works for the "Prime" universe by IDW standards, but this is the "50-S " universe, so I choose to ignore that part.
I turned to Ecto-Zone for many dates and events in the early period (Prehistory to 1982), but I changed things as needed. My biggest sin is moving the entire run of EXTREME GHOSTBUSTERS to 1992, but I hope it doesn't put anyone off so much that they don't give my project a look. I saw no other way to work in the early IDW Comics and their take on Kylie.http://www.televisioncrossoveruniverse.com/2020/01/ghostbusters-after-call.html
Bottom line, everything from 1975's The Ghost Busters to 2016's Ghostbusters: Answer The Call is included, with a lot of the details being changed so they fit a timeline where all the other stuff also fits.