Simply play through a Solo or Band Tour! For Solo play with a guitar (what I did) "Beat It" is unlocked for play about halfway through the game.
You can play Band Hero Drum with Rock Band 2, not rock band 1 ( you have to transfer the songs from RB1 to RB2 to play with Band Hero Drums)
You can play band hero instruments with rock band 2.
You can play Rock band with a guitar hero guitar, but you can't play Guitar Hero with a Rock Band guitar.
No, guitar hero works with band hero, but guitar hero and band hero do not work with rock band and vice versa
Yes, you can. You can also play rock band with guitar hero guitars.
Yes you can play band hero without the drums. In Band Hero (and Guitar Hero 5) You can make any combination of 4 instruments ( Guitars, Drums and Mics )
No, you can on DJ Hero
You can play rock band drum on guitar hero drums band.
Yes
Little richie
I believe that the rock band guitar could play on guitar hero, but guitar hero's guitar would not play on rock band.