yes but why would you play Rock Band if you have Guitar Hero Metallica?
Yes
You can use them with Guitar Hero: Metallica, Guitar Hero Smash Hits, and guitar hero 4
if its on PS2
Yes.
Yes
yes
obviously not
yes, all of the guitar hero controllers are compatible within the same console. For example any guitar hero controller made for ps2 will work on any guitar hero game on ps2.
Mic- PS3 Controller & mic Guitar- PS3 Guitar Bass- PS3 Guitar Drums- Ps3 Drums JA
I am pretty sure that Guitar Hero and Rockband are not compatible together. But if you would like to try it i dont think it would hurt.
You cannot use drums or sing on Guitar Hero 3. The drums work with Guitar Hero World Tour software only.