One possible plot twist could be that Naruto, as a girl, has to infiltrate an all - female organization. He might struggle with the different social dynamics and expectations of being a girl in that context. For example, he could be expected to act more demurely, which would be a big change from his normal boisterous self.
As for Shikamaru, he would probably find the whole situation too troublesome. He might avoid 'female Naruto' at first, but then when he realizes it's really Naruto, he would start to give advice on how to handle the situation in the most efficient way, like how to avoid unwanted attention from other guys.
In character designs, a female henge could be used to create a unique look with a unitard. For example, a henge into a magical being could be paired with a unitard that has sparkles or special patterns to enhance the magical appearance. The unitard could also be designed to fit the specific form of the henge, like if the henge is a bird - like creature, the unitard could have wings - like attachments.
One plot idea could be that a female ninja uses her henging ability to disguise herself in a unitard for a special mission. She might henge into a different gender to infiltrate an all - male organization. Another could be a group of female ninjas who use unitards as part of their new combat gear, and their henges help them adapt to different terrains during battles. For example, they could henge into animals and use the unitards' flexibility to move quickly.
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.
Maybe it could be a new character created specifically for the fanfic. This new girl could be from a traveling group of merchants who Naruto meets during one of his missions. Their encounter could lead to a relationship and ultimately the pregnancy.
Another character could be Hinata. She might be more shy around girl Naruto at first but then they could develop a strong friendship. And the Akatsuki members could also have different interactions with girl Naruto. For example, Itachi might see her as a different kind of threat or an interesting enigma, which could lead to some intense confrontations or unexpected alliances.
It could be an unknown girl from a random village that Naruto just happens to pass by and save from a natural disaster, like a flood or a landslide. Naruto's quick reflexes and strength would allow him to rescue her.
One common theme is empowerment. Since the main character is a girl in a male - dominated Naruto world, stories often focus on her rising above the challenges and proving herself as a capable ninja. For example, she might break gender barriers in the ninja academies or in combat.
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.