Wrong, yet again you are making your own stuff up there is no main thesis of authority and leadership, there are main themes regarding tawheed, nabuwwah etc but nothing on ahlubaith and their divine leadership.
The Quran is a reminder to all the world and not just Arabs. Some people experiencing eloquence of Quran will know it's from God others won't because they don't know Arabic.
But I believe outside of Arabic, Quran has reminders that can prove the proper religion to all humans through reasoning and insights and tautologies and proper signs.
Since obviously everything I'm going to say about Quran you are going say I make it up if I relate it to Ahlulbayt (a), I am going to ask you a very simple question.
Outside of Quran being a miracle what is the proof for Mohammad (s) in your view? Quran reasons a lot, so I want to see how you understand it's reasoning to prove Mohammad (s).
I say this because the way I see it - it has used tactically the past and future and present in a way that if we doubt that past, the present proves it, and if we doubt the present, the past proves it, but this would be circular, and so even the taught of the future, is all about God's way and design of his religion.
I will let you explain how you believe Quran proves Mohammad (s) before continuing on this discussion. In my view, it's impossible to prove Mohammad (s) without proving Ali (a), and so if you understand the Quranic proof for Mohammad (S), you will see it proves Ali (a).
But I will see your explanation first before I expand on this in greater detail and seek to prove it.