Who is the best person?

Q: There are many ahadith that speak about the person who is the best of Muslims. Can we summarize all of those ahadith and say that the best Muslim is the one who has the best character? Also who is this the best person according to the Quran?

Self interpretation of the Quraan

Q: I read somewhere that for example in Tafsir Ibn Kathir, if Ibn Kathir himself has made an interpretation of the Quran we can neither confirm nor deny it since we are humans and we can make mistakes. Is it correct?

What about statements of the Sahabah Kiram which they have made? Also what about the different rulings derived by various ulema?