If Harry goes back to his 5th year in a fanfic, his relationship with Cho Chang might be different. He could be more cautious in approaching her, considering how things ended between them. He might also have a different dynamic with the members of Dumbledore's Army. Since he already knows their potential, he could assign tasks more effectively and boost their self - confidence. His relationship with the Hogwarts ghosts could also change; he could interact with them more, seeking their unique insights into the school's history and secrets.
His relationship with Sirius could be different. He might be more careful and not let Sirius get into danger so easily. Also, his relationship with Hermione and Ron could be strengthened even more as he would be more aware of how important their friendship is.
Well, his relationship with the teachers would surely change. He could be more respectful to Snape, knowing what Snape has to endure. And with Dumbledore, he might be more demanding, asking for more help and guidance right away. As for his classmates, he could be more of a leader, guiding them through the tough times. For instance, he could be more inclusive towards Neville, helping him gain more confidence much earlier.
With Ron, they might not be as close as they were at Hogwarts. Ron might be a bit jealous if Harry does really well in college. But on the other hand, they could also bond over missing Hogwarts and their old adventures.
Well, he might be able to change some of the bad things that happened. Maybe he could stop Umbridge from being so cruel. He could also be better prepared for the challenges that year brought, like the fight against Voldemort's forces.
His relationship with his former sensei, Iruka, would be really interesting. Naruto could go back and show Iruka how much he has achieved, which would be a really heartwarming moment. And with Kakashi, he could share his experiences as Hokage and maybe even learn some new things from Kakashi in the past.
His relationship with Sasuke would be very different. If Naruto stops the Uchiha massacre, Sasuke may not have the intense hatred he had in the original story. They could grow up as friends without the need for Naruto to constantly chase after Sasuke to bring him back.
Link's relationship with his own past self could be a really interesting aspect. If he meets his younger self, there could be a sense of mentoring or even confusion. His younger self might not understand what's going on at first. And when it comes to friends like the Koroks, if he goes back to a time when the Korok Forest was in a different state, their interactions would be new and different. The overall web of relationships would be completely reshaped as he steps into a different time period in Hyrule's history.
His relationship with Kakashi would also change. Naruto could use his Rinnegan - enhanced knowledge to help Kakashi deal with his past traumas earlier. He might also show Kakashi new jutsu or ways of combat that he learned in the future. This would make Kakashi see Naruto in a whole new light and their bond could become more of a teacher - student relationship in reverse.
With his Slytherin peers, Draco's relationship would shift. He might encourage them to be more inclusive and less focused on pure - blood supremacy. This could make him an outcast among some of the more traditional Slytherins, but also gain him new allies who are open to change.
His relationship with his father, Ned Stark, would be different. He could finally have a real father - son relationship instead of the hidden one. He might be able to learn from Ned and become an even better leader in the North.
His relationship with Katara would be very different. He might be able to approach her in a more confident way, knowing what they've been through in the future. He could also avoid some of the misunderstandings that happened between them in the original timeline.
His relationship with Hermione and Ron would be strained at first. They would be confused and a bit scared. But as they see Harry resist the dark side, they would become more supportive. With Dumbledore, there might be a new level of secrecy and mistrust at the start, but Dumbledore would likely keep an eye on Harry to see how he develops. As for the other students, many would be afraid and avoid him, but some might be curious and try to befriend him to see what it's like to be around the heir of Voldemort.