This is A Mutara Nebula because THE Mutara Nebula is transformed into the Planet Genesis at the end of ST2.
Gamma Orionis is in the Delta Quadrant.
Cryptic's position is that the nebula is either back or was never fully consumed.
Gamma Orionis is very clearly in the Beta Quadrant.
The Borg can transport anywhere in the galaxy. They are flanking us from the opposite direction of the Delta Quadrant.
A larger reason is that Children of Khan was supposed to take place in the nebula where Khan was defeated and Cryptic chose to have the Borg turn up in that region of space (because the Borg can turn up anywhere; they use portals) to center endgame around the region of space where the nebula from Wrath of Khan was located.
Yeah I think its clear it is supposed to be further south of the Klinks in Beta.
Nice catch about the Unimatrix Zero reference with Beta 'bordering' Fluidic Space, hadn't thought of that.
Makes sense to me that the Borg would be able to grab a foothold there as it is a distant area of Federation space and the Fed-Klink war would make reaching it initially to drive them back very difficult. It's proximity to Cestus and Gorn space might explain how the Borg assimilated those mega Gorns for use on Defera,