When it comes to Leisha and her relationship with the other members of the crew, I'd imagine the 'Ghost' thing is likely to be more of an issue than any matters of nationality or past military affiliation.  As for Leisha herself...  Well, having been at ground zero for pretty much the single worst atrocity of the war, I don't think she's going to be inclined to hold any grudges against any other former soldiers.  Really, it's probably going to be more of a matter of whether or not there's anyone she gets along particularly well with, to be honest. ^^;