One possible plotline could be that fem Naruto has to learn to control the Kyuubi's power in a different way than in the original series. Since she's female, her approach might be more empathetic, and the story could focus on how she forms a deeper connection with the Kyuubi because of this.
Maybe the plot could involve the Kyuubi having a different view of fem Naruto compared to male Naruto. It could lead to some interesting interactions where the Kyuubi is more protective or has a different type of relationship with her. For example, they might communicate in a more emotional way, and this could drive the story as they face various challenges in the Naruto world together.
One possible plotline could be the two characters starting as enemies or at least with a lot of misunderstandings. As the story progresses, they gradually come to understand and trust each other, and a romantic relationship begins to form.
One possible plotline could be about Naruto and the fem kyuubi fox form teaming up to fight a powerful new enemy. Maybe an ancient evil has been awakened and they have to combine their powers to defeat it. Another could be a story of the fem kyuubi fox form teaching Naruto more about his own chakra nature and how it relates to her power.
Perhaps the story could revolve around the Fem Kyuubi teaching Naruto more about his Kitsune heritage. This could include special jutsu or abilities that only those with Kitsune blood can learn. The plot might also involve Naruto having to protect the Fem Kyuubi from other ninja who fear her power and want to seal her away again.
There could be a plotline where the fem Kyuubi gets into trouble in the village because she's not fully understood as a pet. Naruto then has to defend her and prove that she's not a threat. Also, a plot where they discover a new power together that helps them in a big battle against a new enemy.
A plotline might involve the power dynamics changing due to the pregnancy. Since Kyuubi is a powerful being, the unborn child could potentially have extraordinary powers. This could lead to various factions trying to either control or protect the pregnancy. Also, Naruto's relationship with Kyuubi could deepen on a more emotional and personal level as they prepare for the new life.
One possible plotline could be that the female Kyuubi uses her power and influence to guide Naruto in a different way than in the original story. Naruto, being submissive, follows her advice which leads to new adventures and challenges. For example, she might direct him to explore a different aspect of his ninja training.
Well, it could start with the fem Kyuubi being in love with Naruto. Since she has negative feelings towards Kushina, she could begin by influencing Naruto's view of his mother. For example, she might show Naruto 'alternate' versions of Kushina's past actions that are not entirely true. As the story progresses, the fem Kyuubi could try to isolate Naruto from anything related to Kushina, like the Uzumaki clan heritage that Kushina represents. And perhaps, in the end, she realizes the error of her ways when Naruto discovers the truth about his mother. However, this is just one possible set of plotlines in such a complex and potentially controversial fanfiction concept.
One possible plotline could be the yandere fem Kyuubi constantly trying to protect Naruto in overly possessive ways. For example, she might scare off any potential rivals for Naruto's attention, even his friends at times. Another could be Naruto initially being oblivious to her yandere tendencies and just seeing her as a strange but powerful ally. As the story progresses, he has to deal with the consequences of her extreme behavior.
One interesting plotline could be the exploration of their relationship in the face of Naruto's journey to become Hokage. The fem Kyuubi might support Naruto in his training and political challenges, adding a unique dynamic to the story.
One interesting plotline could be Naruto's struggle to balance the power of Amaterasu and his connection with the Fem Kyuubi. Maybe he has to use the powers in harmony to defeat a powerful new enemy that threatens the Hidden Leaf. Another could be a love triangle situation where Naruto's bond with the Fem Kyuubi and the influence of Amaterasu create some romantic tension. It could also involve Naruto using the unique abilities of both to explore a new realm or unlock some ancient secrets.