Personally, I think as soon as you ask them to join the party it should go to a character creation screen for that character and you build it from the ground up. That way you can tailor your party the way you want. As is I actually want to play Lohse as my ranger because im interested in ranger style play and that characters origins. But if i do this then I will get sebille starting as a ranger and not something i need, like a healer. Allowing to choose the character build either at the beginning of the game or when you meet them would lend a bit more freedom in player choice.