I read/heard in several dialogs with Larian personal that you can change the classes of the companions (after meeting Withers). Wyll as Fighter was mentioned for example, while the game still refers to his Mizora Warlock patron story. If such a strange and non-sensical stuff is possible, I'm quite sure they don't block Shadowhearts Cleric subclass.
I seemingly have to address the Knowledge domain more. I'm a bit surprised that it is seen as a possibility for a Shar girl. I'm curious how the domain is made in the game.
