KS, take a Shinx called Gentleman (if male) or FairLady (if female).
First and foremost, Shinx must have Rivalry as its ability. This Shinx always puts the opposite sex first - if it could hold a door open for them, then it'd be doing so all day long if it had to. Unfortunately, its preference for the opposite sex had led to an ugly disdain for those of the same sex, whom Shinx feels are not respectful enough. The consequences of this character defect have far reaching consequences.
If Rivalry would boost the power of a move, Shinx may only attack directly using its most powerful attack (after STAB and effectiveness). If Rivalry would lower the power of a move, Shinx may only attack directly using its least powerful attack (after STAB and effectiveness, ignoring immunities). If Rivalry has no effect (i.e. opponent is genderless), then Shinx may use any move it likes.
There are no requirements to evolve into Luxio. However, to evolve into Luxray, it must solo Crasher Wake (if male) or Fantina (if female), as Luxio considers these people to be especially masculine/feminine. Byron is clearly more manly than Crasher Wake, but soloing a Steelix seems a bit tough...