Well, Tsunade could be a supporting character. She might be worried about Naruto being so far away and engaged to someone from a different place. She could send some of her trusted shinobi to check on Naruto. Also, Konoka's teacher or mentor could be in the story. This person could give Konoka advice about her relationship with Naruto. And then there are Naruto's animal companions like the toads. They could show up and give Naruto some wisdom regarding his new relationship.
One possible supporting character could be Naruto's friends from Konoha. They might visit Naruto in Konoka's world and be a bit skeptical at first about his relationship with Konoka. Another could be Konoka's family members. Her father, for example, might be initially hesitant about Naruto but then come to accept him. There could also be some local villagers in Konoka's place who become friends with Naruto and help him adjust to the new environment.
One possible plot could be that Naruto, after achieving great things in his own village, travels for some reason to the world where Konoka lives. They meet by chance, and Naruto's heroic nature and kind heart immediately attract Konoka. As they spend more time together, they start to develop feelings for each other and eventually get engaged. Their engagement might face some opposition from people who don't understand their relationship, but they overcome it through their love and determination.
Konoka's healing magic could be very useful in the Naruto world. For example, if Naruto gets injured during a battle, her magic could heal him faster than normal medical ninjutsu. Setsuna, with her combat skills, could teach some of the Naruto characters new sword - fighting techniques. In return, Naruto could teach them about chakra control and how to use shadow clones in combat. Their abilities could create a really powerful and unique fighting style.
Gaara, Temari's brother, would surely be a significant supporting character. He would be involved in the decision - making regarding Temari's marriage. Hinata could also be a part of it, maybe as a friend to Naruto, offering her gentle support and understanding throughout Naruto's relationship journey with Temari.
Iruka sensei could be another one. He could be the one who encourages Naruto to become a dentist in the first place. He might also bring in students from the Ninja Academy for dental check - ups, which would help Naruto's practice grow. And of course, Naruto's friends like Shikamaru and Choji could also be there. Shikamaru could use his intelligence to come up with efficient ways to manage the patient flow, while Choji could be the one who tries to make the waiting area more comfortable with his love for food, like suggesting the best snacks for patients to have while waiting.
Shikamaru could be a supporting character. He might be the one who sent Naruto and Sasuke to the bathhouse area as part of a strategic plan for a mission. He could be waiting outside and making snarky comments when they come out. Another could be Sakura. She might be worried about Sasuke being in the bathhouse with Naruto and come to check on them, causing some comical moments.
Kakashi could be a supporting character. He has a connection to both Naruto and Sasuke. He might try to stop Naruto from going too far in his revenge, reminding him of the values he once held. Another could be Hinata. She could be there to support Naruto emotionally, giving him the strength to face Sasuke. Rock Lee might also be involved. He has always respected Naruto and would probably join him in his quest, especially if he believes Sasuke has become a real threat to the ninja world.
Well, Iruka - sensei could be a supporting character. He might check in on Naruto from time to time to see how he's doing under Kakashi. Tsunade could also play a role. Maybe she has some special tasks for Kakashi and Naruto as part of Naruto's apprenticeship. And then there are Naruto's other friends like Choji and Kiba. They could be involved in group training sessions or missions that are related to Naruto's training with Kakashi. For example, they could be the ones Naruto has to protect during a mission as a test of his skills learned from Kakashi.
Sakura could be Naruto's personal physician or his stylist. Given her intelligence and her skills in the original story, she could play an important role in keeping Naruto in top shape for his shows or making him look his best. She would be the one to patch him up if he gets injured during a stunt or a performance.
Kakashi could be a significant supporting character. He could provide Naruto with some advice or even join the battle alongside Naruto for a while. Another possible supporting character could be Hinata. Her gentle presence and belief in Naruto could give Naruto the extra motivation he needs during the fight.
Another plot could revolve around Konoka and Setsuna traveling to the Naruto world. They could get involved in the Chunin Exams. Konoka might be intrigued by the medical ninjutsu there and Setsuna would be ready to fight any opponents. They could form an unlikely alliance with some of the Naruto characters, like Shikamaru, who could help them strategize their way through the exams and the various challenges in the Naruto world.