nope To the first point, this is likely the case as Activision has been sued by No Doubt over the use of the band's likeness in Band Hero. Courtney Love has also threatened to sue over Kurt Cobain's likeness in Guitar Hero 5.
To the second, it would make sense to return to a rock & roll-based focus as the Band Hero product can be used to reach a broader music audience, while the Guitar Hero brand still resonates with rock fans.
GoNintendo also claims that music from Queen, KISS, and Black Sabbath have been confirmed and there will be a "quest mode" narrated by KISS singer Gene Simmons.
We should know more at E3 2010 when Guitar Hero 6 is most likely revealed. Guitar Hero 6 is slated for release in the second half of 2010 for the PlayStation 3, Xbox 360, and Wii. There will be no further Guitar Hero games on the PlayStation 2.