The nogitsune could also be a major antagonist. It thrives on chaos and mischief, and a powerful wizard like fem Harry Potter in its territory would surely draw its attention. It might try to possess her or use her magic for its own evil purposes.
Maybe some new, more powerful werewolves from outside Beacon Hills who don't like the idea of a witch meddling in their business. They could see her as a threat to their way of life and power structure, and thus try to drive her out of town or even worse, try to kill her.
Well, maybe she'd use her magic skills to solve the supernatural mysteries in Beacon Hills. For example, she could help the pack with her spells when they face a really tough enemy that normal means can't defeat.
He could meet Scott McCall. Scott, being a werewolf, would be intrigued by Harry's magic. They could become friends and learn from each other. Harry could help Scott better control his werewolf side using magic, and Scott could show Harry how to survive in Beacon Hills' supernatural chaos.
Well, perhaps Harry could bring his magic to Beacon Hills. He might use his spells to help the locals deal with the supernatural threats they face there. For example, he could use a Patronus to fend off some of the dark creatures that lurk in the town at night.
Stiles. Stiles is Scott's best friend and he's very intelligent. He could be the one who initially is suspicious of Harry but then realizes his value. Harry and Stiles might bond over their shared problem - solving skills, though in different ways. Harry with his magic and Stiles with his deductive reasoning.
The Nogitsune could also be a great antagonist. It thrives on chaos and mischief. Percy's presence and his powers would be something the Nogitsune would want to either corrupt or use for its own evil purposes. It could try to possess Percy or those around him to gain access to his demigod abilities.
One possibility is that Harry's arrival in Beacon Hills shakes up the existing power dynamics. If there are different factions in Beacon Hills, like werewolves, hunters, etc., Harry could be an unexpected wildcard. He might form alliances with some while being a target for others. His magical abilities could either be a great asset or a cause for fear among the residents. For example, if there's a conflict between the werewolves and some dark force, Harry could use his magic to help the werewolves in ways they never expected, but this might also draw the attention of those who don't trust magic in the town.
Scarecrow could also be a main antagonist. His fear - inducing toxins could be a real problem for Harry. Harry would have to use his magic to counter the effects of the fear toxin and also figure out a way to stop Scarecrow from spreading it all over Gotham.
The Death Eaters could still be the main antagonists. They might see Fem Harry Potter's new - found goddess - like powers as a threat to their plans of taking over the wizarding world. So they would try to stop her at all costs.
The traditional wizarding authorities could be antagonists. Since Fem Harry Potter is into pirate stuff which might be seen as unorthodox in the wizarding world, they could try to stop her from following this new path.
The plot could involve Hermione using her magical skills in the world of Beacon Hills. Maybe she helps the pack with some supernatural threats using spells and potions. For example, she could create a protection spell around the town to keep out certain dangerous creatures.