Yep he's more of a citizen of the world than an American, otherwise I don't think he would have ever been considered. It also helps he was held in high regard by Pope Francis.
If you're talking about crossing country borders, then maybe. If you're talking about distance traveled, I would venture to guess that Americans on average travel further distances. The United States of America has states larger than many countries in Europe.
Citizens of the world usually refers to cultural exposure and appreciation for differences around the world. I have never seen it refer to distance travelled, however I can see how some Americans can use that definition to try and change the topic
Are you under the impression that the United States doesn't have a diverse mix of cultures, or that people here don't appreciate differences? That's literally what the "great melting pot" thing is all about.
I believe the question implied "in living memory". Popes notoriously don't directly speak up even against atrocities such as genocides, let alone act on it (with levers that are most certainly in their control, such as excommunications).
Pope John Paul II was a crucial figure in the fall of communism in Poland, even though he never opposed the state directly - just the fact that he was Polish and that the state couldn't censor his speeches and visits and demonstrated to the deeply religious nation that there is a path outside of the the one dictated by the state that is credited with a significant contribution to the forces that eventually led to the events of 1989.
