Of course, there's always the chance to call him a "...Class 5 Full-roaming Vapor. Real
nasty one, too!"
I could agree with the whole no-named bit. Actually, if he doesn't show up, I'll be okay with that, too.
See, the RGB cartoon was done in Japan with an Anime background, and most times in Anime there's always some kind of minion/pet type character--in this case, they chose "Slimer" because he appeared at the end of the movie.
The reason I'd be okay if he didn't make many appearnaces (or none at all) in this comic series is because in the RGB cartoon he gets re-introduced and suddenly named "Slimer" there. By not having him in the comic by name, that leaves the continuity open to move from the movie to the RGB with these new comics, even though they are set in today's time frame, as the segue way.
If they did it animated, I'd love to see it done like Batman: The Animated Series where they paint all the backgrounds against a black background, or airbrush them. It gives it that darker mood. Obviously in the day-time shots there would be lighter backgrounds, but for the interior and night shots it would be best to paint the art against a black background.