Is there anyway we can get Multiplayer categories set up for this game? I may just be a dumb idiot and overlooking the category.

there is no online multiplayer campaign, so no there is no category.

yes there is a 2 player campaign.... why does it have to be online for it to count? guitar hero 2 was the first game to introduce 2 player story mode and in guitar hero 3 you have to beat the 2 player campaign to unlock the songs suck my kiss, reptillia , cities on flame,sabotage, and monster in the 2 player campaign player one plays guitar and player 2 plays the bass (or rhythm if theres no bass chart)