I'm not sure who Aku specifically is. Aku could be a person with a great imagination who tells all kinds of stories, like adventure stories, fairy tales or even true - life stories.
Since I'm not familiar with the 'little ayah story', it's difficult to provide details. It could be about a little girl named Ayah, perhaps her adventures or daily life experiences, but without more information, it's just speculation.
I'm not sure about the 'little ayah story', so I can't determine the main characters. It could be Ayah herself as the central figure, and perhaps there are other characters like her family members, friends, or neighbors who play important roles in the story, but this is just my assumption without having read it.
Yes, there might be. Some romance novels feature characters with diverse backgrounds and occupations. An Ayah CEO could be an interesting character in a modern - day or cross - cultural romance novel. It could add an element of mystery, power, and cultural richness to the story.
It could be someone from the Naruto universe who doesn't like Naruto's newfound fascination with Aku. For example, Danzo might see Naruto's interest in Aku as a threat to the stability of the village and try to stop Naruto from further exploring Aku - related things. So, Danzo could be the main antagonist in this case.
The character of Aku could be developed in a 'pregnant Aku in Samurai Jack fanfiction' by exploring how he interacts with the world around him differently. He may become more reclusive as he doesn't want others to see his 'weak' state. Or he could become more aggressive in trying to protect his pregnancy, which would be a new aspect of his character. Also, his relationship with his own power might change. Maybe he has to find new ways to use his magic that don't harm the unborn, which would force him to grow and adapt in ways he hasn't before.
One idea could be a crossover where Aku accidentally opens a portal to the Naruto universe. Naruto, being the curious and brave ninja he is, decides to explore Aku's world. They could start off as enemies, but gradually come to understand each other's motives and end up teaming up against a greater evil that threatens both of their worlds.
I'm not sure of specific novels that have exactly an Ayah CEO character off the top of my head. However, you could start by looking at novels that focus on multicultural relationships or business - themed romances. Some independent or niche publishers might be more likely to have such unique character combinations in their books.