Yeah, I understand you. The game focuses on the player being the leader of the clan and at the same time, the clan being an extension of him. Perhaps the only way for what I proposed to happen is that when the schism occurs, each heir has a separate clan. In the case of the player who decides not to take the inheritance, he would have his own clan (Maybe Tier 1) and the heritor(by the succesion law) would become the player's clan leader.
I should add that the idea of regency seems great to me, perhaps it could also be extended to the wife. For a roleplay theme such as Leonor de Aquitaine or the She-Wolf of France, etc.