As far as music, typically less "ordered" societies have a more personal level of music. In modern society, most performed music is done by professionals, and basically all distributed music (aside from a few videos on YouTube and the like) is professionally-done. When you take away those distribution channels, though, more people will play music just for themselves and their friends. This means more evident casual players, a proliferation of small, portable instruments (flutes, banjos, and the like), much less recorded music, and so on.
As for when to set the game, one possibility is that your ship is the first operational one that one of the more outlying planets has managed to get going. Thus, in a kind of Fallout concept, your job is to go out there, find out what in blazes happened to everyone else, and help get your planet back on its feet.
A few other thoughts:
- Communication lines should be few and unstable. News should not be even remotely instantaneous.
- Murk and radar noise would probably be more common, as gear decays.
- Any operational carrier ships would probably be repurposed as ad-hoc space stations.
- Destroying ships would be wasteful even for pirates. Pretty much everyone should have the "disable and board" AI.
- Fuel will be a problem. Maybe slap a bunch of solar panels onto the ships? It'd be neat if you could work that into the ship models, but I know what kinds of art problems you have.
- Petty warlords would replace the pirate lords of yesteryear. A small fleet of battle-capable Vipers with a Valkyrie "command craft" would be able to effectively terrorize a system for a not insignificant amount of time, if I'm reading your tech levels properly.