Kushina would take care of baby Naruto very tenderly. She would make sure he is well - fed before sleep, perhaps by breastfeeding him or giving him a warm bottle. She'd also check his diaper and change it if needed.
One great fanfic is 'The Early Days of Naruto' which beautifully depicts Minato and Kushina's relationship with baby Naruto. It shows their tender moments together and how they start to teach Naruto about the ninja world from a very young age. Another good one is 'Naruto's Family Beginnings' where the focus is more on the family dynamic. You can really feel the love Minato and Kushina have for their baby. And then there's 'Baby Naruto's World' which goes into detail about how Naruto's presence affects the village even as a baby, and how Minato and Kushina are at the center of protecting and nurturing him.
Well, a fanfiction could explore how Minato and Kushina's love for each other is reflected in their care for Naruto. Their strong bond as a couple helps them create a loving and stable environment for their baby.
Well, a big theme is the 'what - if' factor. What if Kushina had lived and been able to raise Naruto? Fanfictions explore this by showing their relationship in different ways. There's also the theme of strength. Kushina was a strong ninja, and in these fanfictions, she imparts that strength, both physical and mental, to baby Naruto. And of course, the theme of hope. The idea that with Kushina by his side, Naruto's future would be filled with more hope and less loneliness as a baby.
In fanfiction, Kushina might also interact with baby Naruto in a protective way when facing potential danger. Imagine a situation where some rogue ninjas are after Naruto for some reason. Kushina would put herself in front of Naruto without hesitation, using her chakra chains to fend off the attackers. And after the danger has passed, she would comfort Naruto, telling him that he is safe now and that she will always protect him.
One common theme is the mother - son bond. Since Kushina is Naruto's mother, these fanfics often explore the deep love and connection she has with her baby son. It could be shown through her sacrifices for him or the simple joys of taking care of him.
One possible reason could be mind control. Maybe an enemy of the village found a way to manipulate Kushina's mind and make her turn against her own baby. Another reason might be a misunderstanding. For example, she could have been tricked into believing that Naruto was a threat to the village in some way.
One possible development for Naruto is that he begins to show signs of leadership. Even as a baby, he might gather the other village kids around him and lead them in some small play - adventures. For Kushina, she could develop a more nurturing side. She might start to think more about the well - being of the whole village because she realizes that Naruto will grow up in this environment. So, she could be involved in activities that improve the living conditions in the village, all because of her love for Naruto.
The theme of legacy is also quite common. Since Minato is the Fourth Hokage, fanfics might explore how he wants Naruto to carry on his legacy. And Kushina's strong will also gets passed on to Naruto in these stories. They also often show the simple joys of family life, like spending time together at home, which is a contrast to the dangerous ninja world outside.