His personality would be significantly different. Since house - elves have a very different culture from wizards, Harry would grow up with different values. He could be more empathetic towards the underprivileged in the wizarding world, like the house - elves themselves. He might also be less concerned with the pure - blood/muggle - born divide, as house - elves don't really care about such things. Additionally, he would have a strong sense of duty towards those he considers family, which in this case would be the house - elf that raised him. This sense of family and loyalty would be a core part of his personality.
He'd likely be more humble. House elves are humble creatures, and growing up with them would instill those values in Harry. He wouldn't be as boastful as he sometimes is in the original series.
His personality would probably be more aloof. Since basilisks are solitary creatures, Harry might not be as sociable as in the original story.
Harry would likely be more fearless and brash. Kenpachi is a bold and fearless fighter, and his influence would make Harry less hesitant. For example, when facing a bully like Draco, Harry might immediately react with physical force rather than just trading barbs. He would be more upfront and direct in his approach to problems.
He might be more reserved. The Malfoy upbringing would likely make him less impulsive compared to his canon self. He could also be more calculating in his actions.
If Harry Potter was raised by Luffy, his personality would change significantly. Luffy is always cheerful and optimistic, and this would seep into Harry. Harry would be less haunted by his past and more focused on the present and future. His sense of humor would also be different. Luffy has a very simple and direct sense of humor, and Harry would probably adopt some of that. He would be more likely to laugh at the simple things in life. In addition, Harry would be more impulsive. Luffy often acts on impulse, and Harry would be more likely to do the same, which could lead to both great adventures and some trouble. His loyalty would also be more like Luffy's, fierce and unwavering towards his friends.
He'd probably be more in tune with nature. Since mermaids live in harmony with the sea, Harry might have a deep respect for all living things. He could be more calm and collected, like the stillness of the ocean depths.
Harry would likely be more confident in his pure - blood status, at least on the surface. Since he's raised by the Malfoys' twins, he'd be exposed to the pure - blood elitist culture from a young age. He might be more calculating and less impulsive than in the original story, having learned from the Malfoy family's shrewd ways.
He'd likely be more fearless. Dragons are fear - inspiring creatures, and growing up with them would make Harry less intimidated by threats. He might be more direct in his actions and less likely to second - guess himself.
Harry would likely be more gruff and less trusting. Growing up with Moody, who was always on guard, Harry would have learned to be more cynical. He might not be as quick to make friends as he was in the original story.
He might be more reserved and empathetic. Remus is a rather quiet and introspective character, and Harry would likely pick up on those traits. He'd be more understanding of those with differences, like werewolves, given Lupin's condition.