Own fiction 100%. There may be similarities in names and such. Hegemony, for example, is a prominent culture in the Hyperion book series. Clans Remnant being in Mechwarrior I had no idea about. If you want something else, you can also call them the Legion Alliance or even Nomad Fleet. They won't mind. 
Xin: a race of intelligent cephalopods ranging up to 9 meters in length. Their ships are semi-organic, semi-sentient and filled with water to sustain the Xin.
Clans Remnant: actually three alien races. One looks like an armored cat on two legs, one like a gas sack with bioluminescent tentacles dragging behind and the third like a small upright armadillo. They have junkyard ships which look like rusted boxed hammered into shape with guns slapped on. Ok, cooler than that, hopefully.
Hegemony: very tall, very thin, clad in all white and always wearing hoods. Their ships are golden/black with sleek lines (much like the Xin actually) interspersed by sections of rough machinery etc.
XSelenS, thanks for the offer! I have already made a selection of new planets which will get in the Last Stand mod... there probably won't be any new star types as the vanilla set covers most realistic ones. I checked out your mod - good effort there, keep it up (here's a tip - try to desaturate you coloured backgrounds a little, it will make them fit in better. Always use slightly desaturated colors for backgrounds as they're easier on the eyes, especially on long gaming sessions).
Work continues to progress well. The website won't be ready for yet anoter week though, so I'll just post Leviathan screens/renders and lore here as usual when its done. I'll save the Second Teaser movie for the website though. 
It'll have lots of new Xin units in action as well as a snipet from a CGI intro sequence...
