Put it this way:
Whichever NPC crew members you end up occupying the niche of will end up in low passage.
I'd prefer to keep Ktarle defrosted for reasons of plot; so a Medic is not the best option
The group has several good engineers, Pilots, Astrogators, Comms, Computers and Sensors people.
They only have one good gunner (Tuan)
The group doesn't have anyone at all with a background in Geology, Mining, Prospecting or Survey. Or T/Gravitics for that matter
I'm not necessarily saying they need one; but a character with those skills is covering a new niche.
At which point Belter turned Scout starts to look good...