No. You can't, and probably shouldn't be able to alter the base character concepts for the scripted characters. You're free to build them any way you want, but their basic attributes are unchangeable, so obviously some favor certain skillsets over others. Notice that's different from me saying I don't wish I could create my *own* party from scratch.
The scripted companions are deliberately written characters with unique backgrounds and identities. Their basic attributes help define who they are. Red Prince's dialogue and personality would not feel as authentic if he were a shifty rogue instead of a noble knight.
Im fine with that. Well defined scripted characters add life and personality to a story, and are better at forming player attachment than some generic character with no distinct voice of their own.
I don't feel that this is a valid argument to support this. This is a game and the primary function of a game should still be on playability. You can already take these base characters and reshape them yourself, so there's absolutely no justifiable reason for not being able to tailor them to fit your current playthrough.
Personally, I like having companions along that aren't faceless mercenaries with no backstory. But I absolutely loathe feeling that points are wasted, or that their base builds just don't match how I want to play. Since I can already make Lohse into a knight or a ranger when I select her as my main character, there should be nothing that prevents me from fully customizing the companion version of her.