Harry could also become more refined in his manners and social skills. The Greengrass family is likely to have a certain level of propriety and sophistication, which would rub off on Harry. He may learn to interact more gracefully with the upper echelons of the wizarding society.
His view of family might be completely different. Instead of the cold and neglectful experience with the Dursleys, he would have a loving and supportive family. This could make him more open - hearted and trusting, and perhaps less cynical about relationships in general.
Harry's character could change in terms of his confidence. Growing up with the Delacours, he may have more exposure to high - profile wizarding events and people. This could boost his self - assurance. He may also become more open - minded as he experiences different magical cultures. Instead of just relying on what he learned at Hogwarts, he would have the Delacour family's knowledge to draw from. And he might develop a more flamboyant side to his personality, influenced by the Veela - like qualities of the Delacours.
His magical abilities could develop in new directions. Since different families have different focuses in magic, the Greengrass family might encourage Harry to explore areas he hadn't before. For instance, if the Greengrass family is known for their potions skills, Harry could become an even better potions - maker. His self - confidence may also grow as he is part of a new family structure that supports and encourages him in different ways compared to the Dursleys.
He might become more refined in his manners. The Malfoys are a very proper pure - blood family, so Harry would likely be taught to act more like them. For example, he'd probably have better table manners and a more sophisticated way of speaking.
His story would change a great deal. For starters, he might not have the same connection to the Dursleys. His early years would be filled with the Greengrass family's values and lifestyle. He could be more attuned to pure - blood politics from a young age.
He would probably be more in tune with nature. The Inuzuka's lifestyle would make him more aware of the natural world around him. He might be less bookish than in the original and more hands - on with physical activities like running and training with the clan.
He'd probably become more brooding. Growing up with Dracula would expose him to a darker side of magic and life. He might not be as quick to trust others as he was before. His sense of humor might also change, becoming a bit more sarcastic and dry, like the typical Dracula - like characters.
Harry might become more confident. Rebbekah is a strong character, and under her influence, Harry could learn to be more assertive. He'd no longer be just the boy who lived, but a part of a different magical family with different values.
His living conditions would change drastically. Instead of living in the wizarding world, he'd be in palaces. He'd have servants and all the luxuries that come with royalty. His friends at Hogwarts would be replaced by new acquaintances in the royal circle. He'd have to adapt to a very different set of rules and expectations.
Well, it would change a great deal. For one, he might get better grades in Potions as Snape would be more likely to give him extra help. Also, he might be more protected from the likes of Draco Malfoy and his gang, since Snape would not tolerate any bullying towards his adopted son. Harry could also have access to Snape's private library, which would expand his knowledge of magic far beyond what he could learn in the regular Hogwarts curriculum.
Harry's character would likely be a mix of confusion and determination. He'd be confused by Voldemort's teachings which go against his natural inclination towards good. But his determination to find his true self would remain. He might develop a sort of duality, acting one way around Voldemort and his followers, but secretly being someone else.