Can Universe Sandbox even show civilizations, or is it purely just for purposes of planetary systems and spatial mapping? Nothing against it, I'm just more interested in the geopolitical climate than I am planetary bodies.

Xenocentrism is preferring your own species to others. Like the [i]Galactic Empire[/i] in Star Wars was xenocentric in that it largely favored humans over aliens. A Pro-Graal government would be xenocentric in that it alienates non-natives. So if the Earth government was pro-Graal it would support Humans and alienate other races, besides the Graal (who is the hand that feeds them).

The reason I asked about your people breathing chlorine is that the manner in which Chlorine reacts with Hydrogen would make a planet rich in Chlorine filled with HCl (Hydrochloric Acid). Your oceans would be muriatic acid, your atmosphere would be corrosive as soon as it mixed with moisture or water vapor; but no worries -- I'm just a moron.