I really don't see any contradictions. Just the protagonists character being developed over the last 10 + years of the series.
If everyone knew who Naruto's parents were from the start, and why the 4th sealed the fox in Naruto, everyone would have thought differently.
I am pretty sure that he still wants to be the Hokage, but we don't really hear it to much from him directly. This is probably due to the fact that he has other goals, that are probably more important to him at the moment, and he focus's his attention on those, versus his dream of Hokage.
It has always been hinted at who his father was, Jiraiya said in the first series he was taking Naruto as his apprentice, because of his resemblance to the 4th. Granted Jiraiya knew who his father was, but it was still not revealed until much later.
Is there some kind of time line that state's exactly how long he was training with the toads? I have always wondered how long he was with the toads myself.
He obviously was always part of the Uzumaki clan. The whole chain of hatred thing has been a vital part of the entire story, just with different names attached to it, and it needs to be seen in a different way, and on different scales.
There is a fine line between arrogance and self confidence. People are that are seen as arrogant are typically only seen that way by people that have low self confidence.
I don't believe he is OP. As of right now he is only on par with the Raikage. We haven't seen what he can do fully with his new powers, so maybe he has peaked (which is highly unlikely). We also don't know what Kabuto, Tobi/Madara, or Sasuke can do yet.