You know, I always thought the same between Male M!U and Katarina, but it seems they are not paired.
As for classes, it depends on gender chosen. Males have mercenary, cavalier, fighter, archer, knight and mage I believe. Female has peg knight, myrmidon, cavalier, archer and mage.
Backgrounds affect growth rates I believe.
As for epilogue, I don't think it affects, but it would be cool.
By the way, I searche for this, I haven't played the game yet.