Throwing my lot in with Goldenboko too.

As for the actual question, I'd say Auron has an impact on Tidus, for sure. You notice that Tidus says "This is my story" during the game and is met with a bit of a frosty response; he doesn't realise that it's not just about him, which is a stark difference from his celebrity life in Zanarkand. But Auron, being that sagely bastard that he is, allows Tidus to become arrogant, and the fact Auron is a big deal in Spira doesn't help either.