Interesting! Are outsiders allowed, or perhaps areas that were once colonies but were basically ignored and became self-sufficient as things declined? etc?
If by outsiders you mean not a part of the empire, then yes. You can start outside of the empire. As for the latter you prob can, I am playing a Hivemind race, we got some pirates, we got a megacorp, one guy has a group where the majority of the workforce and military is automated drones/robots and thus has a very small human population, another one has some psionic space squids with a largely enslaved population if I recall. GM seems to be fine with whatever as long as it is interesting and thought out to some degree.
If you are interested in joining, it is best to join the discord for ease of communication and discussing things with the GM, I think the old link expired but I can prob get a new one if you want