I always seem to figure out the series and the characters better when I write these. Toilet bound Hanako kun really makes for great display of different secondaries.
Hanako is such a screaming snake secondary I haven't seen in a while. He is always smiling like he is on to some big crazy joke no one is getting. The way he loves to tease people with harmless but pointed jokes and insults. The way he shifts to fit the person he talks to, going from serious leader roles with the other wonders to friendly carefree ones with people, to warm and moving ones in emotional moments. A trickster by heart, but in the best way. The way he can laugh in face of danger or crack a joke like it's nothing, act so cheerfully in critical situations calms people down and makes him incredibly reliable. He doesn't come off as powerful and dangerous as he is, which also makes people underestimate him, but it's also because he wants them to relax and be comfortable. Because that's the way he wants to win their trust and that's seriosuly sweet.
Yet he also killed his twin brother Tsukasa, while being his abuse victim. A confident leader wanting to repent. A boy hiding deep sadness, who gave up all his dreams and killed himself, only to get stuck at his school grounds with his abuser as his main rival. Not getting rest even in death and with responsibilities sometimes so heavy, he thinks he can do the best out of, if he doesn't burden others with them. Shouldering things alone behind a giant smile and cocky eyes, easy jokes and playful shenanigans. I'm not sure what this says about his primary. He is fair to people and a benevolent wish-granter, but he also gets terribly attached to people, especially Nene in a snake like way. He loves to touch her, invade her personal space, tease her, protect her, spite her to get attention. She quickly becomes the centre of his world, what reminds him of being human, the first reason we see him get serious for.
At the same time he strikes me like a burned snake primary. Hanako protected his younger brother despite the abuse he was getting from him by keeping the causes of his injuries a secret. He gave up on his dreams and future because he felt like he couldn't get anywhere with his brother nor leave him. He killed him, only to hate himself for it and spend his afterlife repenting, crying and breaking down every time he meets his victim as a ghost from the guilt. With a friendless background, he goes out of his way to help people and keep a balance between the supernatural and the living, while vigorously defending the ghosts for needing to scare people to get the attention they need to survive. The apparitions can't live without rumours and people believing in them and so Hanako defends and allows them missteps to give them that chance. The apparitions are "his" people, his kind, so he is at their side. But he also fixates on Nene, his first real friend and her well-being, while allowing her to make the best choices for herself and not one's most comfortable for him. While he likes keeping people at a distance with his cheerful facade, he is incredibly moved to have them care about him, pouty when he gets ignored, embarrassed when he reveals something more personal and distressed when Nene wants to know more about him. Very difficult character to sort, especially since I only watched the 12 episodes of the anime adaption and not even the manga revealed Hanako's full backstory nor his ending. But I would say a burned snake primary who went too far in his devotion that it destroyed him, slowly unburning as the story progresses and he finds new people to care for and makes real friends that genuinely care for him.
Nene is much easier to sort. A glory hound lion primary, she just wants to be popular and have the most handsome boy as a catch. She is in love with the idea of love, with good looks, with a cool reputation, with her own cuteness. She is also a lion secondary, barging in on people, acting on her emotions and impulses, saying what she is thinking without concern, no sense for planning whatsoever. Her honestly, impulsiveness and open heart are her best, worst and most prominent qualities. A double lion is an unusual sorting for a girl, or at least I don't encounter it very often. It doesn't make her screaming, overbearing or eager to fight, she is just very straightforward with her desires and emotions and often gives in to her impulsivity.
Her instincts are right too. Nene doesn't know the first thing about Mitsuba, but feels from his behaviour he isn't a bad person and makes a friend out of him. She writes Kou off as not nearly as handsome and interesting as his brother, but she is still kind and worried about him. She complains about being Hanako's assistant, but she enjoys her role in helping other wonders and apparitions, spreading the right rumors around the school to help the living and the dead alike. Remarkable is also her ability to befriend almost everybody in the story - not in the hardworking connector badger way but in a spontaneous natural way. When she has a dilemma about leaving Hanako for the mermaid princess's offer, she goes to every apparition she met during the story and they treat her as a friend, giving her advice. People flock to Nene like they flock to lions, being my point.
Now Kou Minamoto is a loud lion secondary like Nene in a typical boy's way - he throws himself into fights, charges, confronts, challenges. He is reckless and quick to act without thinking. But his driving force is the most obvious out of the cast - he is a badger primary. His mission and legacy as an exorcist is really about protecting as many people as he can. He has the typical badger arc of realizing ghosts were people too and have feelings, wishes and regrets. At first he wants to destroy Hanako when they meet, only to slowly realize he actually does much more good than harm as the leader of the Seven Wonders. That's how he starts to observe, stands up to his older brother for their limiting views on who is worth saving and starts helping ghosts in order to set them free instead of fighting to destroy them violently. He is such a good-hearted kid under the brush attitude of a wild lion, he is easily the most selfless out of the trio.
Kou's badger heart also nicely complements the group. Hanako cares about his chosen people. Those are other Wonders and ghosts, and then the two friends he finds in Nene and Kou. He is willing to stand up for them even against Tsukasa, someone he couldn't stand up against for himself even in life. And maybe that's also why he is partially so paralyzed and breaks down when he sees him - cause Tsukasa as his twin brother was his snake person too and it was him who made him burn - but Hanako blames only himself.
Nene brings in the self-interest and thrust for acknowledgement and fame that the caring self-deprecating Hanako and the people motivated and kind Kou lack, while giving it her own girly spin of finding love and getting a popular older boy as a trophy. And Kou just does the most noble thing, wanting to protect and care for others with a dedicated but healthy badger core.