In terms of the Cullens' family relationships, in a split second, Carlisle could be put in a situation where he has to choose between his family and his principles. For example, if a new vampire law is created that goes against his beliefs, and his family is in danger because of it. This would force the family to re - evaluate their relationships with him and with each other as they deal with this new situation.
For Naruto and Hinata, their relationship could develop in a unique way if Hinata starts teaching Naruto some of the more refined aspects of the Hyuga clan's techniques. This would create a new level of closeness as Naruto respects Hinata's skills. And with Tenten, she could be the one who arranges little 'get - togethers' for the three of them, which slowly builds a stronger bond between all of them.
Their relationships could be developed uniquely by having them participate in a magical tournament that's not like the Triwizard Tournament. They are on different teams but have to cooperate secretly to overcome some corrupt judges. Draco might start to see Harry and Hermione in a new light as they work together to expose the wrongdoings. This shared experience outside of the normal Hogwarts rivalries can bring them closer.
Their relationships can be developed uniquely by having them participate in a mission that requires them to rely on each other's skills in unexpected ways. For example, Ino's mental abilities, Naruto's brute strength and positive energy, and Sasuke's strategic skills could combine to solve a mystery that has been plaguing the village. This would force them to respect and trust each other more.
Their relationship could be developed through a shared mission. For example, they are both tasked with protecting a special, ancient artifact that has the power to bring peace to their world. Working towards this common goal, they gradually learn to respect each other's abilities. Alec might be impressed by Seth's loyalty to his pack, and Seth could come to admire Alec's strategic thinking as a vampire.
Maybe Carlisle and Bella could bond over their shared experiences of being different from the norm. Carlisle is a 'vegetarian' vampire, and Bella is a human who is in love with a vampire. They could have deep conversations about how they both struggle to fit in with their respective worlds and find solace in each other's understanding. This would add a new layer to their relationship and make it more unique.
Their relationship could be developed uniquely by having them communicate through a special form of magic that only they share. This magic could be tied to their emotions, so when they're happy, it creates beautiful glows, and when they're sad, it sends out a signal that only the other can understand.
Well, for a unique relationship development, Emrys could act as a mentor to Belle in understanding magic, which in turn makes Rumplestiltskin (Gold) jealous. This jealousy could lead to Rumplestiltskin trying to prove himself to Belle in new ways. He might start to let go of some of his darker tendencies as he sees Belle growing closer to Emrys in a platonic way.
To develop Roseline uniquely, you could give her an unusual hobby like collecting antique keys. This hobby could tie into the story in some way, like leading to a mystery she and Bella have to solve. For Bella, you could make her really good at parkour, which gives her a different kind of physicality and confidence. When they face challenges, their skills can play important roles.
The relationship between Sasuke and Naruto could be developed by having them actually communicate as the reincarnations of Indra and Ashura. They could have deep discussions about the burden of their pasts and how to break free from the cycle of hatred. For example, Naruto could share his experiences of always trying to find the good in people, which might make Sasuke re - evaluate his own views.
Aaron Yan could be developed as a very shy person when it comes to expressing his emotions, except through his music. In the fanfiction, GuiGui could be the one to break through his shyness. As for GuiGui, she could be developed as a person who has a photographic memory. This could be useful in many situations, like helping Aaron remember his lyrics or important details in their adventures. It would also make her a very intelligent and resourceful character.