Smarts I'd definitely have to say goes to Auron, though I suppose experience would be more appropriate than sheer intellect. Being dead, he has an understanding the inner workings of Sin, Spira, and the true Yevon, he knows more about his world than all people in it except perhaps the Maesters. Also I would say Auron is the most wise. When Tidus and everyone else was losing their cool and thinking with hearts instead of their heads, Auron was always the voice of reason. He also showed wisdom in letting the others learn for themselves the true face of Yevon, when he could've just told them.

Toughness, definitely Auron. In addition to being a natural born tank stat-wise, he was able to suffer a fatal injury, and still force himself all the way down a fiend infested mountain, just because there was something he had left to do. Then he just kinda said, meh, **** dying, I'm Auron, I'll leave when I'm ready to leave. He wears sunglasses and carries a jug of some unknown alcoholic beverage. He uses an unnescessarily large weapon. Auron is 6 feet of brickshitting awesome. Nuff' said.