Consider: Critical Role Firefly AU.
- Vex and Vax as a pair of smugglers, barely eking out a living, but enjoying their freedom. Born to an Alliance politician and a rim-planet farmer, they never really felt welcome in either world, they took to the Black in a crappy little ship and made it their home.
- Pike as a doctor the twins picked up when she was looking for a ship that’d help her find her missing foster brother, Grog. She comes to like them and elects to stay.
- Grog as the hired muscle of the twins’ crew, who was offered the job after they rescued him with Pike.
- Scanlan as a companion hitching a ride with the twins to get to his various clients on the cheap. His mother died in a Reaver attack when he was young.
- Keyleth as a university student who is “studying abroad” for her dissertation on terraforming and the rim worlds and ends up as a long term passenger on the twins’ boat. She’s terrified that her research won’t be good enough.
- Percy as an engineer the twins hired after they sprung him from a jail on some backwater moon and found out he’s quite nifty. He has episodes where he isn’t responsive to others and/or goes into a state of ruthless hyperfocus where he achieves alarming feats of dexterity and marksmanship. There others know little about his past beyond the fact that the Alliance thinks he’s dead.
- The ship is called the Greyskull.