Well, the races released now are on planets that were controlled by existing factions, so we couldn't really kick them off the planet, so they get to control a homeworld. However, for races where their homeworld doesn't exist, it will be owned by Darkness, along with all the no building stuff that comes with it. However, any other planets in the system (if any) will be colonisable by players and factions like any other uncontrolled planet.