B. There's no need to separate the guitar parts. (In fact, if you were to do that, you wouldn't be able to hear Al singing while you play. Where's the fun in that?)
Not true. Try downloading some of the Rock Band and Guitar Hero series tracks. They have the song in song.ogg and the guitar in guitar.ogg. That's how the game is supposed to work. All those other songs that don't have the tracks separate are a waste of time - they're not like playing Guitar Hero but more like playing Dance Dance Revolution on your fingers.