Naruto would probably be very surprised. He has heard about Rin from Obito and Kakashi. So when he actually meets her, he might be at a loss for words at first.
Naruto would likely be excited. He's always eager to meet new people and make friends. Meeting Rin would be like meeting a piece of the village's history. He would probably start asking her a million questions about the past, about Kakashi when he was young, and about Obito. He might also be a bit sad thinking about how her life ended so tragically in the original story, and he might be determined to make sure she has a better experience this time around.
He would be extremely excited. Goku has always been curious about his parents, so he'd probably have a big smile on his face and lots of questions to ask them right away.
Ash would probably be very excited. He might run towards Serena with a big smile on his face.
He would probably be overjoyed. James Potter was a loving person, and the chance to meet his son would be a wonderful moment for him. He might immediately pull his son into a big hug and start asking all sorts of questions about his life.
At first, Goku might be a bit shocked. But then, his natural friendly and curious nature would take over. He'd be eager to learn about her, about his family. He could show her all his cool moves and tell her about his friends on Earth. And he'd be really happy to have a family connection that he's been missing all this time.
He would probably be shocked at first. Just imagine seeing an older version of yourself. He might be a bit skeptical too, thinking it could be some kind of trick.
Both of them might also feel a sense of unease. Seeing a version of themselves from the future could make them realize how much they are changing and how uncertain their future really is. It could also make them question their current identities and goals. They might start to have an internal struggle as they try to reconcile their present selves with the potential future versions they are seeing.
Naruto would first be cautious, but then his friendly nature would take over. He'd try to find common ground with the dragon. Since he has a connection with all living things, he'd attempt to communicate with it on a deeper level. He might share his dreams and stories with the dragon, hoping to gain its trust.
Harry might be a bit skeptical at first. He would question whether this is really his future self or some kind of trick. But as the future self starts to share some personal details or knowledge only Harry would know, he would start to believe. Then, he could become eager to learn from his future self, asking all kinds of questions about his future, his friends, and his role in the wizarding world.
He's probably shocked at first. Naruto has grown up without his parents, and suddenly having grandparents appear is a huge surprise.
He might be surprised. He's used to his own life and adventures, and seeing it twisted and turned in fanfiction could be unexpected.