Good question!
In Aiha's case, I figure your characters probably know the broad strokes - that she's a hacker who grew up on a station, that she's clearly in hiding or on the run from something, maybe that she runs an AI in her mech that she's rather protective of - but probably not the details of her history with FENRIR, why she left the station, or what exactly she's got to hide, since she'd be pretty cagey with that information without a real good reason to trust you.
Alternatively, if this is their first job together and they didn't get much of a chance to talk on the way over, your character might not know much about her at all.