Those dead adult drones on the cube? It's a good bet that among them were the kids' parents, assimilated at the same time as them. Except for Icheb's, of course.
What kind of upbringing did First have that made him so 'committed' to staying in the Collective over returning to life as an individual?
Word of God says the Borg baby was returned to her people, and multiple fanfictions say she was adopted by Marla Gilmore from the Equinox. But onscreen? The lack of an explanation combined with her medical situation makes it seem likely that she didn't survive.
