I had at one point, maybe 15 years ago, picked up a Mego style set of Sam Hain and maybe Janine? It also came with a cardboard facade of the firehouse. I have no idea what happened to it, maybe I donated it because it had no business being in my collection because at the time, good cartoon Ghostbusters didn't exist.
If I had to pick between the big ghosts that are available, I'd have gone with Boogey Man. Easily the creepiest, though the guy that comes with Ray grosses me out with those ghosts crawling into his stomach.. eugh