You guys might not agree and claim "no its the younger son" or "no its all of the senju/Uzumaki"... but no these 3 are the ones who inherited the will of the Sage. The will that gave them the power from childhood to decide to change the world. The will that can only be learned through harshness. The will that makes the most impact.
The starter: Shinobi religion
The first one: Shinobi system..
The second one: Akatsuki.... Obito fans or Nagato fans can cry or claim w.e they want. But the true creator is this man.
The third one: You already know though =D
And furthermore evidence is the basis that all 4 believe that peace should come through understanding.
I agree, but I'm not 100% convinced about Yahiko. He was a leader who believed in peaceful solutions, but was not depicted as the almost foolish idealist that Hashi and Naruto seem to be. Foolish=the ability to keep believing despite evidence to the contrary.