Bill Ko is right. And this is a not a hard science game. Otherwise, there would be exactly ZERO other races in the game. Modern Astrobiology and Modern Cosmology says that there are no other intelligent bipeds out ther. There are no other tool users (as we are) out there. There is most likely many small, early eco systems on many worlds, but most worlds are not stable enough environmentally long enough to get anything approaching a jelly fish, let alone "higher" life forms.
So, that leaves us non-planet bound life forms. Whose sense of time and basic concepts would be so alien to us that we would have no common framework to communicate with. VERY large astro creatures, living in nebula, and being on the size scale of our solar system themselves. We won't even recognize that they are living beings... just as they won't recognize us as anything beyond "bacterial" life forms.
GC is pure science fantasy. We don't know that the freeze people using cold. For all we know, they download a person's brain, process the body for raw materials, and ship out. When the colony worlds get to where they are going, they land and "clone" new bodies for the colonists, and upload their "virtual brains" back into the body. This would also explain why a colony ship is effectively unlimited for its carry capacity. It's just data storage. And why Troop Transports aren't... they are actually carrying the body of the trooper.
It just depends on what you are most comfortable with. What makes the most sense to you. If "cold sleep" coffins offend your personal universe, then please, envision your favorite views. It's only a game, after all, and based on "what would be more fun", not "what is more realistic".