Stargrave doesn't have crew types, that's more a Rogue Stars thing. If you mean what would fit for your captain and first mate, pretty much anything should work. Let's see:
Biomorph - might be a stretch, but if the guy's a mad dok (or a mad dok's pet project) or some kind of mutant it could work
Cyborg - spell it cybork and you're done
Mystic - weirdboy, obviously
Robotic Expert - big mek, be sure to call his charges tinboyz for old school cred
Rogue - some kind of sneaky git, maybe a kommando or loota boss
Psionicist - another flavor of weirdboy
Tekker - another flavor of big mek
Veteran - kind of the default warboss or nob background
As far as your soldiers go anything works. Even ones like the hacker/codebreaker types could be flavored as junior meks or their grot assistants. The "guard dogs" are squigs - or maybe unusually enthusiastic grots, since they're pretty weedy in combat but fast.