To answer the question about the Dark Knight...It may be a good idea to make a female Dark Knight, if the Dark Knight is anything like is says, I'd be willing to bet that the Dark Knight Skills will be based on MA rather than PA. So, having a Female Dark Knight would be the same reason to get a Female Samurai...to concentrate primarily on the use of skills and techniques rather than physical attacks.

Summoner/Arithmetician is a solid combo, fun for ultimate destructive powers. (**hint** get a Mime with the Summoner/Arithmetician to create ultimate destructive powara)