Phineas provides many examples of freedom from concern with conforming to society's expectations. He was completely comfortable with himself and didn't feel any need to abide by the rules affecting others if he didn't agree with them. Of course, Finny could talk and/or charm his way out of any discomfort or outrage or other reaction that society might have in reaction to what he did.
In his haste that morning Finny had not unexpectedly used a tie for a belt. But this morning the first tie at hand had been the Devon School tie...."I wore this, you see, because it goes with the shirt and it all ties in together..." Mr. Patch-Withers' face had been shifting expressions..."That's probably the strangest tribute this school has had in a hundred and sixty years." He seemed pleased or amused in some unknown corner of his mind. Phineas was going to get away with even this.
Leper preserved his personal freedom by following his own instincts instead of trying to conform with a world he didn't care about or understand. At first, he didn't see any reason for speed when skiing, and he didn't see any reason to be offended if others thought he was strange for not seeking more excitement - an attitude not applied only to skiing.
Brinker spent much of his time at Devon being the ultimate conformist, following the rules he helped to develop in his position with the student government. He revelled in the importance and the power he thought such activities brought him, but by the end of the story he was wishing for a way to avoid the military involvement that was facing all the graduates. Conformity was not so appealing, and he rebelled at the stories of the glory of fighting in the war told by his father.
"I'm enlisting," he went on, "I'm going to 'serve' as he puts it, I may even get killed. But I'll be damned if I'll have that Nathan Hale attitude of his about it...I'm not that kind of hero"