If Naruto becomes a girl, her character development would be quite distinct. She could start to view the world from a more empathetic perspective. Her experiences as a girl could make her more aware of the inequalities in the ninja world, especially those related to gender. This new awareness could fuel her drive to make changes. For instance, she might start campaigns or initiatives to give female ninjas more equal opportunities. She would also have to adapt to a different physicality. As a girl, her body might be different in terms of strength and agility, which would force her to develop new fighting styles and strategies, thus leading to a different kind of character growth.
One interesting plot twist could be that Naruto, as a girl, has to deal with different types of relationships. For example, Sasuke might view her in a whole new light, leading to a more complex love - hate dynamic. Another could be that the female Naruto uses her new - found femininity to deceive enemies. She could pretend to be a damsel in distress and then surprise them with her ninja skills. Also, the story could take a turn where the female Naruto becomes a role model for other female ninjas in the village, changing the traditional gender roles in the ninja world.
A minor character like Choji could experience a 'turn of a hero' by suddenly mastering a new and powerful form of his Akimichi clan's techniques. Maybe he discovers a way to combine his food - based jutsu with some sort of spiritual energy, allowing him to defeat an enemy much stronger than himself. This would make him a hero in the eyes of the village.
Maybe Naruto was trying to protect Sasuke from a certain danger. There could be a curse or a powerful enemy that targets male shinobi. So, Naruto uses a risky jutsu to transform Sasuke into a girl to keep him safe. Or it could be that Naruto found a strange ancient scroll with a transformation technique that he thought was something else and when he used it on Sasuke, it turned him into a girl.
One interesting plot twist could be that the hero, who was thought to be Naruto all along, turns out to be someone unexpected like Iruka. Maybe in a battle against a powerful enemy, Iruka suddenly reveals hidden powers and a deep connection to a long - forgotten ninja art. This would completely change the dynamic as everyone had their expectations set on Naruto being the ultimate hero.
Well, the plot could start with the twins finding some sort of magical object or spell that they think would be hilarious to use on Harry. Once they turn him into a girl, Harry might be initially shocked and confused. He could then have to deal with the reactions of his friends like Ron and Hermione. Ron might be really surprised and a bit clumsy in his interactions at first. Hermione could be more practical, trying to find a way to reverse the spell. And all the while, Harry (as a girl) might discover new things about himself and the way others perceive him.
Another reason might be as a form of punishment or lesson. Athena, being the goddess of wisdom, could be teaching Percy something about seeing the world from a different perspective. By turning him into a girl, he might gain new insights into how females are treated in the world of the story, whether it's in the demigod community or among mortals.
I'm not sure of a specific fanfic with that exact plot. But you could try searching on fanfic platforms like Archive of Our Own. There might be some creative works there where the twins play such a prank on Harry and turn him into a girl in a fictional and often humorous or interesting story setting.
The story of Marie Curie is a great one. She was the first woman to win a Nobel Prize and the only person to win it in two different scientific fields (physics and chemistry). Her discovery of radium was a huge breakthrough. This story can turn on a girl's interest in science as it shows that women can be at the forefront of scientific discovery.
One idea could be a crossover where Naruto enters the Incredibles' world and teams up with Elastic Girl to fight a new villain. They could combine Naruto's ninja skills and Elastic Girl's stretching abilities to defeat the bad guy.