Sorry to bump such an old topic, but I figured I might have a couple of snippets of info that may have slight relevance to the topic at hand.
Ribos actually originates from Dr Who, a planet involved in the search for something called the Key to Time (do a websearch for further information) - someone at Volition was probably a fan.
Ikeya is the name of an astronomer, Kaoru Ikeya. Probably most notable for
comet hunting - again someone making the game might've come across it in their information gathering and decided to use it. Either that, or Ikeya hasn't discovered this star yet
As far as I can tell, the other two (along with these examples) don't exist. However, there's still plenty of space, even local space, to be searched, and given that there are a couple of hundred years until this fictional universe springs into existance, there's not really anything to stop anyone from keeping these stars fictional.
