Obviously, Sonic himself would be likely involved. He might be the one to discover baby Infinite. Tails could also be there, using his intelligence to figure out what happened to Infinite. Knuckles might get involved in protecting the baby Infinite. And of course, there could be other characters like Amy who would be interested in taking care of the baby.
In this fanfiction, perhaps the transformation into a baby for Infinite in Sonic Forces is a result of some sort of magic or experiment gone wrong. The story might then focus on how he interacts with the Sonic universe now that he's in this vulnerable state. He could befriend characters who were previously his enemies, as they see him in a new light. It could also explore how he grows and develops, even in his baby form, and how that might change his future when he eventually returns to his normal state.
Tails is also quite popular. Fans like to write about his inventions and how he uses his intelligence to help Sonic out. There are many fanfictions where Tails comes up with some amazing gadgets to defeat Dr. Eggman.
Obviously, Aria herself is the main character. Her family members like her mother and father could be important characters, offering support or having different opinions. Her best friends would also be likely to be involved, providing emotional support or getting into some friendly arguments about how she should handle the pregnancy.
Obviously, Infinite himself is a must - include. His complex character with his powers and his connection to the Phantom Ruby can drive a lot of the story. Sonic is also essential as he is the main hero and his interactions with Infinite can be really interesting. Tails could also be included as he can provide the technical support and his loyalty to Sonic adds another layer to the story.
Sonic himself is always popular. He's the main character of the Sonic franchise, so in crossovers, he often takes center stage. His speed and heroic nature make him a key figure.
Well, obviously Hermione herself is the central character. But other characters could include her friends like Harry and Ron, who might be completely unaware of her secret life at first. There could also be new characters introduced, such as a mysterious mentor who is guiding Hermione in her secret magical activities. Maybe a powerful witch or wizard from a far - off land who has some connection to Hermione's family in the past.
Obviously, Elliot Stabler could be involved. He and Olivia have a long - standing relationship in the show, and he could be a source of support or conflict depending on the story. Fin Tutuola could also be there, as he's her colleague and friend, and might offer some comical or heartwarming moments as he tries to help her out. Captain Cragen could be in the story as well, dealing with how Olivia's pregnancy affects the work environment.
Another potential character could be Naruto. Naruto has his own set of ninja powers and a strong will. If he were in a crossover with Vegeta, their different ideologies about power and friendship could clash or they could learn from each other. Naruto's ability to never give up might inspire Vegeta in some ways, or Vegeta's raw power could amaze Naruto.
Definitely the Naruko clone herself. Then there could be Sasuke. He might be intrigued by the clone and try to understand her existence. Also, Kakashi could be involved, maybe as a mentor figure to the clone, guiding her. As for the 'lemon' side, there could be some random attractive ninja from another village who catches the clone's eye and they develop a romantic relationship.
In this fanfiction, characters like Luffy from One Piece might be involved. Luffy's carefree yet determined nature would contrast with Ichigo's new god - like presence. Also, characters from the Bleach universe itself could have new relationships with Ichigo. For instance, Aizen might see Ichigo's godhood as a threat or an opportunity, leading to a complex plot development.