A potential plot development might be that Voldemort, upon hearing that the Potters are alive, would be enraged and try to attack them again. This would lead to a new series of battles and challenges for Harry and his parents. They would have to work together to fight off Voldemort and his followers. Also, Harry's parents could help him unlock new magical abilities or knowledge that he didn't have access to before because they are more experienced wizards.
In such a fanfiction, Harry would likely be in shock. His world view has been centered around their deaths for so long. He could be hesitant to trust this new reality. But once he does, he'd have a whole new support system. His parents could teach him magic they've learned in their 'hidden' years. This would make him even more powerful and give him a different standing among his peers.
In this fanfiction, Harry might have a magical encounter where his parents' spirits guide him. Maybe they reveal secrets about his family's past that Dumbledore had been keeping from him for his own protection.
One way is that Harry discovers a spell that allows him to communicate with the dead. Using this spell, he contacts his parents. They give him advice on how to defeat Voldemort, like a secret weakness of the Dark Lord.
Well, it could be about Harry Potter finding a will left by his parents. Maybe in this fanfiction, the will contains secrets about his family, his heritage, or some sort of magical items or powers that were meant for him. It might also reveal things about his parents' past and their relationships with other characters in the wizarding world.
His confidence would probably soar. Knowing he has his parents, who are likely strong ninjas, supporting him would make him feel more secure. He might become a bit less reckless as he now has people who care about him deeply and he wouldn't want to worry them.
Well, for one, Harry would grow up in a loving family environment. He wouldn't have to live with the Dursleys. His magical education would likely start much earlier and be guided by his parents, especially James who was also a very talented wizard. His confidence and self - esteem would be much higher as he wouldn't have the emotional baggage of being an orphan.
The plot would change a great deal. For one, Harry wouldn't have to live with the Dursleys. He would grow up in a loving magical household. He'd be more confident and perhaps less of an underdog. His parents would be able to train him in magic from a young age, so he might be more advanced in his studies when he gets to Hogwarts. Also, the fight against Voldemort would be a family affair, with James and Lily Potter being key players in the battle against the Dark Lord.
Naruto would probably want to introduce his parents to all his friends. It would be a big moment for him to show off his family, especially to Sasuke. His relationship with Sasuke could also be affected in a positive way as Naruto now has a more complete family.
Well, one thing that could happen is that Naruto would be overjoyed. He has always longed for a family, and to suddenly find out his parents are alive would be a dream come true. He'd probably have a million questions for them about his past, why they had to be away, and what their lives were like. And his relationship with his friends might change a bit too, as he now has this new family aspect to his life.