What characters get their levels and jobs updated in the chaos route?

I have been working on Merlin assuming that the jobs i trained will carry over once he becomes Oberon like it did with Alice/Ilias. But i am not actually sure if Oberon is just gonna be a new character like it was with the 4 bandits or a form swap of Merlin and if these levels carry over.

At the same time i was wondering what other characters will just get their levels updated once you get them in the chaos route.