Yep, these are all established characters I've written about before (well, except for the ship, but he's a fandom character, so he's established too.)
Their backstory is that they were part of a secret genetic experiment to combine human and alien DNA to give humans telepathy. This was illegal, so it was done mostly by one mad scientist working alone, though he was paid and supported by others. Then the government found out what was going on and raided the lab, but in the chaos the girls got away from it, and decided they didn't want to go back. They managed to stow away aboard a ship to a station some distance away, and from there they've gone on to begin exploring and learning about the galaxy.