Well, I think that Zash does not give a damn about gender of her apprentice.
She wants someone strong in Force, so that she would be even stronger. She might prefer a girl as her apprentice, but she just rolls with whatever she has (also, Andronikos is lame, so more reason to not play Female SI
I think he disliked Ffon because he was not that strong in Force, and he was an idiot who just got through because of his Sith blood.
As for race, I am still leaning more and more to Zabrak, because of the voice-overs, as they fit the race really well, maybe even more than Humans