No you don't
You Can Play With just guitar as there is a solo guitar mode
Guitar Hero is a game where you "play" musical instruments to songs. Basically you play the note that is prompted. All Guitar Hero games feature guitars, and Guitar Hero World Tour also features vocals and drums as well.
Yes
Yes, all Activision Music/Guitar hero instruments are compatible with other Activision Music/Guitar Hero games on the same system.
Yes. all guitar hero instruments, for the same system, can be used for other Guitar Hero games/Music games also from activision like Band Hero.
get a multitap
Probably a little of both...
you need a guitar to play ALL guitar hero games.
Yes but it might not have all the features.
Yes, the controllers can be used for all guitar hero games
It should work for any Guitar Hero game for the PS3.
No, on all systems Guitar Hero III only supports guitar and bass.