No it was not released for the PS2
No. Sorry.
Yes
yes, the ps2 rock band controllers are actually ps3 controllers but they are ps2 compatible
Rock Band games on PS2 only support PS2-style guitars and PS2/3 Rock Band guitars and drum kits. Guitar Hero: Aerosmith and newer on PS2 support all instruments from all consoles that the games have note charts for (so no drums on GH:Aerosmith but 360 and PS3 drums work on all full-band GH games).
yes
Yes!
No, you can only buy additional songs if you have Rock Band for the Wii, PlayStation 3, and Xbox 360.
yes
The rock band controllers will work for both PS2 & PS3.
XBOX 360 - It is already out for XBOX 360 PS2 - It is already out for PS2 PS3 - October 19, 2008 (It takes longer to make it for the PlayStation 3 than the XBOX 360 or PS2 - go to Rock Band 2.com or Google.com to find more info about Rock Band 2)
Sure the PS2 game works
the ps2 kramer (GH3) and the guitar hero 1&2 guitars work for ps2 rock band games