Yes any guitar is compatible with any game
The guitar controllers (for PS2) will work, yes. But the drum/mic controllers, no.
The Guitar Hero III guitar is completely compatible with Guitar Hero: World Tour provided you're still using it with the Wii.
Yes it will
yes
yes it does
No, which sux the big one!
If it's for the same system, yes.
No, Rock Band 1 was released way before Guitar Hero World Tour so the drums aren't compatible. Also the guitar hero world tour drums have cymbals and the rock band doesn't. In the end: You can't back track.
All guitar hero controllers are compatible with every guitar hero game
Yes
First turn the guitar on and then connect it to the wireless receiver
no sorry