Harmonix logo on the bottom
Permission to use Rock Band assets
BandFuse’s developers said that when they showed their work to Harmonix co-founder Alex Rigopulos, who helped develop both Guitar Hero and Rock Band, he said it was the game that Harmonix had originally wanted to make.
Also there's been talk of the vocal engine being from Rock Band 3, and as well that Harmonix consulted on their difficulty levels.
I doubt we will get an official statement before the game releases (November 2013 maybe).
But regardless, here is something to talk about.