you can only get female tactical and engineering officers and male klingon science officers if they are randomly assigned to you through a quest reward or the exchange. The BO requisition vendor doesn't have those three gender/class combos available.
I have a blue tactical female Klingon... since she had superior Life and close combat stats I wanted to train her purely melee skills and give her a Bat'leth... well - I guess the AI is broken here, as she just crowls into fetal position as soon as the fight starts and doesn't do anything. I have to drag her manually to every enemy and after lunge or leg swipe she refuses to continue with her Melee Weapon. No wonder she is an outcast of the empire
EDIT: I got mine as an "in between" crew assignment in the mission log (whatshallIcallit?)