I'm sure probably Coulson will "come back from the dead," but could this not be a prequel set before the Avengers maybe?
Is he to be in every episode as a regular, or just the pilot?
I read an item saying that some comment had been made that ambiguously implied that he might only be in the pilot. But I'm skeptical of that, since Whedon's words when Gregg's involvement was announced were, "He's headlining the S.H.I.E.L.D. show and always was." "Headlining" means having the lead role, not making a cameo in the pilot.