I understand why they are not there in multiplayer so playing through the campaign cooperatively would certainly be a nice touch for sure... i think the devs missed a trick there for sure

Given that the story elements are not present in Chapters 1 to 9 when playing multiplayer in the current version I cannot see them being in EE as effectively they stop game-play
The maps and objective order is identical to single player and multiplayer Chapters 1 to 9 it is just that the cut scenes are not there