Apparently, the people in the stasis tubes always were in those stasis tubes. Or at least Fred Noonan has no truck with idiotic stories about "space aliens" - an unlikely situation were he once part of a slave revolt against space aliens.
So the story seems to go that the Briori hijacked about three hundred people from Earth in 1937 for their slave mining project, but kept them in stasis until needed. The folks they did take out of the tubes eventually rebelled and killed the Briori - but for some reason, they did not wake up all of their companions. Or perhaps they woke up nobody, there only having been this small bunch left, for reasons only known to the Briori.
Evansville is the great-etc.-grandchild of one of those who did take part in the original revolt. He is not related to either Earthart or Noonan or Hayes or Nogami. But he relates to them, as part of the bunch that were the actual forebears of the current population.
Now... Why were these four in particular never woken up before Janeway came? Kim's scans refer to five other facilities, presumably with eight chambers in each of those, too - all empty. So, out of 48 pods (for 300+ people? Why would the other chambers be equipped with more pods than this one?), we get four people left inside. Were they rejected because they were inferior (Noonan might have been declared dying of alcoholism, say)? Were they simply the last ones left in a systematic reviving of suitably small batches of slaves? If so, how come there were three hundred slaves awake at one time, capable of performing the revolt? That is, why were the slaves woken up in small batches?
Might of course be the origin story is but a myth. Perhaps there were Briori, but perhaps there never was any slavery. Possibly the humans who woke up were the villains of the piece, and the four were left asleep because they were the only half-decent folks around. Or then there's a completely different story there.
Timo Saloniemi