At Hogwarts, Harry would have a different perspective on the Houses. Since he grew up with James and Sirius, both Gryffindors, he might have a stronger sense of Gryffindor pride from the very beginning. He might also be more critical of other Houses, or at least have a more one - sided view. His experience in Quidditch would also be different. James was a great Quidditch player, so Harry would have had more training and might be an even better player right from his first year. He could also be more involved in the Gryffindor Quidditch team's management and strategy, as he would have grown up hearing about James' Quidditch feats.
Harry would probably have a different attitude towards Hogwarts rules. Since James and Sirius were known for their rule - breaking at Hogwarts, Harry might be more inclined to bend the rules. He could be involved in more pranks and might not be as afraid of getting into trouble. Also, his relationship with the teachers would be different. Some teachers who were friends with James and Sirius might be more lenient with Harry, while others might be more strict because they expect him to live up to his father's reputation. His experience in the Gryffindor common room would also be different. There would be more stories about his father and Sirius, and he would be part of that legacy from the start.
His Hogwarts experience would be very different. Firstly, he would likely enter Hogwarts with a much higher level of magical knowledge. James and Sirius could have taught him a great deal before he started school. So, he might be ahead in classes like Transfiguration and Defense Against the Dark Arts. Secondly, his social status would be different. Everyone would know he is the son of James Potter, a popular and talented wizard. This could lead to him being more of a center of attention, and he might have a different group of friends. Instead of Ron and Hermione at first, he could befriend students from more well - known wizarding families.
His Hogwarts experience would likely be very different. He might be more popular right from the start, given the fame of both James and Sirius. The teachers might also have different expectations of him. For example, McGonagall might be more lenient as she had a soft spot for James. And he could have a natural talent for Quidditch, inheriting James' skills. He might also be more involved in secretive activities, like Sirius was, and get into more trouble with Filch.
Harry would probably be more rebellious. Remus and Sirius are not exactly the rule - following types. They've both had run - ins with the law in the wizarding world. So Harry would grow up seeing that sometimes breaking the rules is necessary for doing what's right. He might be less hesitant to take matters into his own hands.
His Hogwarts experience would likely be very different. For one, he might be more physically fit and confident in combat situations. He could be less intimidated by the likes of Snape or Malfoy, as the Dragon Slayer would have taught him to stand up for himself. Also, he might introduce some new skills to Defense Against the Dark Arts, like dragon - slaying techniques adapted for magical creatures.
It would be a very different relationship. He might see Hogwarts as a foreign place at first. He'd be used to Odin's teachings, which are very different from Hogwarts' curriculum.
His relationship with Sirius would be extremely strained. Since Walburga was Sirius' mother and they had a very difficult relationship, Sirius would likely see Harry as a product of his mother's influence. Harry, on the other hand, might be initially hostile towards Sirius due to being raised with Walburga's views.
His Hogwarts experience would be very different. For one, he would have a closer relationship with the hospital wing. He might not get into as many dangerous scrapes as in the original story because he would be more aware of the consequences due to Pomfrey's influence. Also, his reputation could be that of a healer - in - training rather than the 'Boy Who Lived'. His classes might be more centered around potions and herbology as he would have a natural inclination towards those subjects.
Well, he'd probably be more of a legacy student. He might be treated with even more respect or envy from the start. And he could have a different group of friends. Instead of Ron and Hermione, he might be closer to his brother's old gang, like Sirius and Remus, from the very beginning at Hogwarts.
He'd probably be more confident. With Sirius and Remus as his guardians, he'd have two strong male figures who believe in him wholeheartedly. Sirius's boldness and Remus's wisdom would rub off on him. He might be less hesitant in taking risks and more assertive in his actions.
In this kind of fanfiction, Harry would likely grow up with a more hands - on and perhaps wilder form of parenting. Sirius was brave and impulsive. He might teach Harry some of his more unorthodox magic skills earlier. Harry would also be surrounded by Sirius' loyalty to his friends and family, which could shape Harry's own values in a different way compared to growing up with the Dursleys.
A major plot point would be the family dynamic. Harry would grow up in a complete family with his father and Sirius as his guardians. There would be a lot of love and support, but also some sibling - like rivalry between Harry and Sirius perhaps. The story could also explore how the presence of James affects Lily's memory. Does Harry grow up hearing more stories about his mother? And how does that shape his view of love and sacrifice? Also, how do they handle the secrecy of Harry's identity? Since James and Sirius are more bold, they might take different precautions compared to what Dumbledore had planned in the original story.