Minato could be developed further by exploring his time as the Fourth Hokage more deeply. For example, show his political decisions and how they were influenced by the presence of the Kyuubi. Also, his relationship with other villages could be explored, especially in relation to the Kyuubi's power. Maybe he had to make some tough calls to protect the village from those who might want to use the Kyuubi for evil.
One interesting plot idea could be exploring how Minato's relationship with the Kyuubi affects Naruto. For example, Naruto discovers some hidden memories of Minato's encounter with the Kyuubi that give him new powers or insights. Another idea is a story where Minato has to return from the afterlife briefly to help Naruto control the Kyuubi's power more effectively. Maybe there could also be a plot where the Kyuubi has a change of heart due to Naruto's kindness and decides to reveal secrets about Minato that no one else knew.
The Fem Kyuubi being banished by Minato could lead to a rift between the village and the Kyuubi. In the story, this could mean that the village is more vulnerable to attacks from other threats, as the Kyuubi was a deterrent. For Naruto, it could mean that he has to face the consequences of his father's actions. He may be shunned even more by the village because of his connection to the banished Fem Kyuubi. Also, the Fem Kyuubi herself may become bitter and vengeful, which could pose a major threat to the village and Naruto in the long run.
Well, it depends on the specific fanfic. Some fanfics might really emphasize Naruto's growth to be on par with Minato in terms of smarts. They could show Naruto learning from Minato's memories or having some sort of spiritual connection that transfers knowledge. However, other fanfics might focus more on other aspects of Naruto's character and not necessarily make him as smart as Minato.
No. In the Naruto series, Naruto is the host of the Kyuubi, not its slave. Fanfics might deviate from the original concept, but in the official story, Naruto has a symbiotic relationship with the Kyuubi. He gains power from it and eventually befriends the Kyuubi spirit.
Kushina could be an important character even though she's dead in the original story. In this fanfic, her spirit or memories could play a role in Naruto's upbringing. For example, Minato could tell Naruto stories about Kushina's feisty personality and her love for the village.
Well, Naruto has always been alone in a way, and a Fem Kyuubi banished by Minato would also be alone. Their relationship could start from a place of mutual loneliness. Naruto might offer her protection, and in return, she could offer him her power and wisdom. They could bond over their shared experiences of being outcasts in a sense. The Fem Kyuubi could teach Naruto more about his own powers, since she has a connection to the chakra within him, and this could lead to a strong and unique relationship.
There's a fanfic called 'Minato's Return'. In this story, Minato somehow returns and gets to see Naruto's growth. It's really interesting to see how he interacts with Kushina, who is also there in the story, and how they both guide Naruto in new ways. The descriptions of their family bond are heartwarming.
Well, Naruto has had the advantage of learning from many great shinobi over time. He also has a unique bond with his friends which could potentially give him more strength. Minato, on the other hand, had a shorter lifespan to develop his powers. Naruto has had more time to grow and surpass his father in strength.
One great Fem Naruto Kyuubi fanfic is 'The Nine - Tailed Fox's New Host'. It explores how a female Naruto deals with the power of the Kyuubi in a unique way. The story focuses on her training and how she overcomes various challenges with the help of the Kyuubi's power.