It would be a waste to do SP side if the entire campaign could be ported to MP. I just wasn't sure if you have been able to import the cinematic scripts that cue certain cut scenes in a level.
My work would mostly be in story creation, cinematics(camera angles), and sound (voice acting and effects). The co-op side in my mod is NPC reconfiguration through thier abilities and team placement.
I have never gotten into MP ('cause I get my ass kicked too much)so I don't know a whole lot about how it works.