Maybe there's some room to compromise on this.
Try this:
Some of us are definitely at the movie premiere:
Dr. Joey Williams (his friend is a voice actor on the project)
Peter Kong (he's one of the animators)
Dr. Fritz V. Baugh (won the tickets at a radio call-in contest)
Dr. Peter Venkman (Just a Hollywood thing…)
We somehow drive off the critter that appears, but a bystander is seriously injured. We take him to the hospital. Where we meet…
Dr. Kyle Stevens
“Jiggs”
Unfortunately, the bystander kicks the bucket. Kyle and Jiggs are fired. But Venkman is impressed, and decides to start a team of West Coast Ghostbusters (well, two teams, actually). They two doctors and the guys who helped at the premiere are asked first.
He sets up a job fair to recruit the rest of the team, including an old friend of Leon Hogan. It would be up to Chadderbox, Egon901, and Proton User whether they want to be at the movie premiere or be recruited. He then calls in an injured (or formerly injured) vet of the East Tennessee Ghostbusters, Dr. Andrew Harness, to train the new recruits (Venkman obviously knows a thing or two, but he's too busy to be a full-time contributor.)
(We don't want to overuse Venkman. He's a strong character, and it's easy for him to overpower ours. This is OUR show. Venkman has oodles of fanfics starring him
)
We have our first major case as Ghostbusters, and Leon's pal decides he can't cut it and quits–recommending Leon Hogan as his replacement.