You don't need the scenario packs at all if all you need is multi, just get the 13 mb op2dl whether you have OP2 or not already. (extract into your op2 folder if you have it installed).
It will install all the scenario and other addons you will need to be up to date, and will still work for multi. Insert the CD and turn on music/movies in the game if you still want to see those, when playing.