There could also be some minor characters from the wizarding world who might make an appearance. For instance, Albus Dumbledore might be mentioned or even show up briefly to check on Harry's situation. Hagrid could also be a character that pops up, perhaps bringing Harry to the Dursleys in the first place or coming to check on him later.
Obviously, Harry Potter is a main character as the story is centered around him as a baby at the Dursleys. Then there are the Dursleys themselves - Vernon, Petunia, and Dudley. Vernon is the strict and often cruel uncle, Petunia is the conflicted aunt who has her own issues related to the wizarding world, and Dudley is the spoiled cousin.
Obviously, Harry Potter is one of the main characters. He is the one who has the power to control the Dursleys. And of course, the Dursleys - Vernon, Petunia and Dudley - are also main characters as they are the ones being controlled by Harry.
Obviously, Harry Potter himself is the main character. He is the one with the motivation to fight against the Dursleys due to their years of mistreatment.
Obviously, Harry Potter is one of the main characters. He is the one who is being accepted by the Dursleys. Then there are the Dursleys themselves - Vernon, Petunia, and Dudley. Vernon is the strict and often grumpy uncle, Petunia is the aunt who has always been envious of Lily (Harry's mother), and Dudley is the spoiled cousin. Their interactions with Harry will be central to the story as they shift from their previous negative attitude towards acceptance.
Well, family unity is often a theme. Since the Dursleys love baby Harry, it creates a more harmonious family environment. This is different from the original story where Harry was mistreated. Also, the exploration of how this love affects Harry's magical abilities and his relationship with the wizarding world is common. For instance, he might be more open about his magic to the Dursleys, and they in turn support his journey in the magical realm.
There are indeed. A lot of fanfiction writers like to take the concept of the Dursleys being kind to baby Harry and run with it. They might write about how the Dursleys initially had good intentions but got corrupted by their fear of magic later. Or they could create a scenario where the Dursleys truly care for Harry from the start, changing the whole dynamic of the early Harry Potter story. It gives a fresh perspective on the characters.
One interesting plotline could be Harry showing early signs of magic that the Dursleys try to suppress. For example, he might accidentally make Dudley's toys float when he's angry or frustrated.
Obviously, Harry Potter himself is the main character as he is the one getting back at the Dursleys. The Dursleys - Uncle Vernon, Aunt Petunia, and Dudley - are also main characters as they are the targets of Harry's revenge.
Well, Harry Potter is surely one of the main characters since the title implies it's about him being taken from the Dursleys. There might also be some original characters created by the fanfiction writer to play important roles in Harry's new journey.
It could be Dumbledore. He might have realized that the Dursleys were not the best place for Harry after all and decided to take matters into his own hands, using his powerful magic to rescue baby Harry.
Dumbledore might play a role. He could be the one who encourages Harry to stand up to the Dursleys. He might have some hidden knowledge about the relationship between the wizarding world and the Dursleys that could help Harry. Also, Hagrid could be involved. He could provide some muscle if things get physical. He might also offer some emotional support to Harry, as he's always been like a big, friendly giant to him.