The Federation offered no Resistance.
One drone should have been able to take the entire Federation after they got the phaser frequencies sorted out.
Besides did the Queen seduce Picard by teletransmission into his mind, or was she actually there, as according to a literal reading of the movie, that she must have left before the Cube was scuttled.
All the ships that Cube attacked were not necessarily destroyed more so than boarded and their crews assimilated. The Cube didn't have to release a Sphere, because all that wreckage was recycling itself into a new Borg Fleet... Or at least the larger chunks. Maybe they took back booty, and maybe the Borg issued a retreat order when they saw that the Cube had been lost?
The fact of the matter is that Riley was a survivor of Wolf 359.