I can change it to a K if you'd like.

As for who's the best driver, I can't imagine that naval voidsmen would have much need to learn how to drive - or at the very least, much practice/experience.
The other two... well, either would know how, but Steren has by far the better motor skills, perceptions and reaction times*. She also seems to be leading the group here (Jael has a pretty submissive personality), so I suspect that regardless of their relative skill levels, she'd probably take the job.
* I've just realised I've omitted this from her character description, and I'm not sure why - given she's quite capable of reshaping her own flesh, she's made a few adjustments along the way. Taking some years off the clock, a few cosmetic corrections and generally tuning up her body. So she's somewhat stronger and quicker than you'd expect (although still within mortal limits) even without the active use of her powers.