The Hyuuga may be descendants of Hagoromo's brother.Just semi-confirmed the old statement from Part 1 that the Sharingan and the Byakugan have some sort of connection. Still the question stands if the Hyuuga are also descendents of Indra like the Uchiha or from the Sage's brother. Although nice that he didn't completely forget about them.
Yeah that is currently my favorite assumption. Hyuuga and Uzumaki from the brother, Senju and Uchiha from the Sage. Could also clarify why the two clans originating only from the brother are generally seen as "weaker" then the two who came directly from the Sage.The Hyuuga may be descendants of Hagoromo's brother.