bilbo as an ordinary denizen of the shire, a very fertile planet with a demilitarised civilisation whose only commerce with the neighbouring planets in the galaxy are those of trade, scientific research, diplomacy. they’re protected (though many of the hobbits don’t realise it) by a paramilitary group called the dunedain. the dunedain are extremely good at their job, as the shire has not seen war in a very long time.
erebor as a mining planet, maybe even a diamond planet? its golden towers and spires of its metropolises are the stuff of legend; it was dripping in wealth. and then smaug, a great machine of destruction, a giant AI dragon of nuclear might, destroyed the people of erebor, and thorin and his family, the royal family of erebor, had been evacuated at almost the last minute.
they live a life of wandering from job to job, mostly mechanics, sometimes thieves, and thorin’s ship is a ragtag thing he named after his lost planet, cobbled together from parts he gets for cheap at scrapyards. they’re constantly on the run from patrols from gondor and the elves, as they are really the only law enforcement folks in this galaxy.
gandalf as a mercenary of sorts with a wide variety of connections, concerned about the return of the necromancer in the old space station of dul guldur orbiting mirkwood, as well as the destructive force of smaug, decides to encourage thorin to retake erebor, but stealthily. no need to retake erebor wth an army when you can instead get a saboteur to enter the dragon and shut it down, right?