One of the likely supporting characters is Tsunade. Given her experience and leadership in the village, she could be a source of advice for Naruto and Hinata. She might also ensure that Hinata has the best medical resources available during her pregnancy. Rock Lee could be another supporting character. His positive attitude and loyalty to Naruto would make him eager to help out. He could be running errands for them or helping with any physical tasks. And Neji, if he were still alive in this fanfiction, would surely be there to protect his cousin Hinata and support Naruto as well.
Sakura could be a likely supporting character. She might offer Hinata some advice on married life, as she has been through a lot in her own life. Shikamaru could also be there, perhaps helping Naruto with some of his Hokage - related duties so that he can have more time with Hinata.
In addition to the main group, some fanfictions might include other characters from Inuyasha's demon world. For example, his half - brother Sesshomaru might make an appearance. He could initially be indifferent but later show some form of protection or interest in the unborn child due to family ties. Also, some of the friendly demons they've encountered in their adventures could come to offer their help or gifts for the upcoming baby.
Luna could be a great supporting character. She might offer her unique perspective and be very supportive of Ginny. Also, Harry, being Ginny's brother, could play an important role. He could be protective at first but then come to accept the situation. Neville might also be there, perhaps helping out with practical things like gardening to provide fresh produce for Ginny during her pregnancy.
Alice could be a supporting character. She might have visions about Bella's pregnancy and the future of the baby. Jacob could also be involved, perhaps initially being angry or concerned about Bella's situation with Aro. Carlisle could be another one, as his medical knowledge as a vampire doctor could be useful in dealing with Bella's pregnancy.
Ino could be one of the main supporting characters. She might help Hinata with choosing baby names or decorating the nursery. Shikamaru, on the other hand, could offer some practical advice on how to deal with the changes in life that come with having a baby. And of course, Hinata's family members like her father and sister would also play important roles in supporting her during this time.
Naruto could be one. He has his own experiences and growth, and he might give Hinata advice based on his journey. Her father could also be a likely character. As her father, he would have a lot of wisdom to impart. And Sakura, being a strong - willed and knowledgeable character, could also be someone who gives Hinata advice.
Sakura would probably be a side character. She could be the one who checks on Hinata's health during her pregnancy if that's part of the story. Shikamaru might also be there, helping Naruto with some of the strategic planning for the village while also giving him relationship advice. And Boruto and Himawari would be important side characters as their children, adding a family - centered aspect to the fanfiction.
Sasuke could be a likely character in some fanfiction. Maybe in an alternate universe where their rivalry takes a darker turn, Sasuke might frame Naruto to gain an advantage or to prove his own superiority. It would add a whole new dimension to their relationship.
One potential supporting character could be the Hogwarts professors. They may have different reactions to Harry's situation. Some might be more accepting and try to help, like Professor McGonagall who could use her Transfiguration skills to create things that are useful for Harry during his pregnancy. There could also be some characters from the Asgardian side, like Heimdall, who could be observing the situation from afar and may or may not choose to interfere depending on how he sees the future implications.
Obviously Naruto himself is the main character involved. But his friends like Sasuke, Sakura, and Kakashi are also likely to be involved. Sasuke might be affected by Naruto's wishes, for example, if Naruto wishes for Sasuke to fully return to the Hidden Leaf Village and be at peace. Sakura could also be involved, perhaps in helping Naruto make his wishes come true in a medical or support way. And Kakashi, as Naruto's former teacher, would surely play a role in guiding Naruto in how to use his wishes wisely.