Sanghyuk

First Impressions

Because of their different social circles and Jiyoon's relatively recent transfer to Busan, the Ghost Club interest meeting is their first proper encounter with each other. As expected of Jiyoon's questionable priorities, the initial impression he has of Sanghyuk is that the older is undeniably (visually) cute - so, naturally, Jiyoon hits on him with flirty lines and an excessive amount of eye contact. 

While Jiyoon isn't at all the brightest or most perceptive individual in the room, what he does sense is Sanghyuk's lack of self-confidence, and considering Jiyoon has always been a rather honest-to-a-fault kind of guy, he makes it known to the older that self-confidence is something Sanghyuk should work on developing. It's this kind of no-filter nature of Jiyoon's that causes a rocky start for the two (particularly on Sanghyuk's behalf, for Jiyoon's too dense to realize), and while Jiyoon's seemingly omniscient presence both in and out of the Ghost Club initially doesn't help lessen the one-sided tension, one thing's for sure is that Sanghyuk is good-looking and Jiyoon will be more than happy to stick around if it means being surrounded by pretty people and ghost adventures.

Seojun

First Impressions

While Jiyoon has noticed Seojun around school, the difference in their schedules and class grade means that their first actual interactions take place at the first Ghost Club meeting. Seojun's initial impression on Jiyoon is that the older is almost a replica of his older cousin Jihan in personality - distant, usually keeps to himself, quiet with a surprising and unexpected streak of sarcasm beneath a seemingly intimidating appearance.

However, this doesn't deter him at all. Maybe it's his lack of impulse control for a constant need to talk or maybe it's his tolerance towards Jihan's short temper and mood swings, but either way, something encourages Jiyoon to reach out towards Seojun first in his signature easygoing, open-minded, and talkative nature. Much to his pleasant surprise, any awkward tension many would have expected to occur between them instead melts away, and Jiyoon is happy to discover that the Jeon Seojun others expected to be intimidating is actually instead an approachable and likable individual with a similar daring attitude and an incredibly fun sense of humor.

Seoyi

First Impressions

With them both being part of the popular crowd and sharing similar social circles, Seoyi is a familiar face amongst the sea of strangers upon Jiyoon's first time with all the club members. While they're not the closest of friends, their kindred sociable nature prevents most - if not, any - clashes between their personalities.

Jiyoon does, however, perceive the underlying tensions within Seoyi's friend group, and despite not being the brightest or most intelligent individual in the room, what he does get a sense of is her mixed emotions towards her close friends. He makes it known too whenever she's away from the group, and though he doesn't at all push her to leave or be wary of them, Jiyoon is an honest person and encourages her to become more comfortable with herself rather than maintain a public facade just to please her friends.

Hyeri

First Impressions

Considering Hyeri's reserved and shy nature, they haven't had the chance to properly speak until the Ghost Club, though that doesn't mean Jiyoon treats her as a stranger. Instead, his habit of constantly talking prevents a silence from settling between them, but if anything, that's even worse for Hyeri because it means Jiyoon just doesn't shut up.

Is he put off by her lack of response to his attempts at conversations? Not really, because he's grown so used to Jihan's intolerance of his presence, and while it would be pleasantly surprising if she did begin thinking of him as a friend rather than a parasite, Jiyoon's happy-go-lucky personality is completely fine with their one-sided conversations and interactions for now.

Jiyoon

First Impressions

Let me know what they think of them at first glance! This can be as short as a sentence to a complete thought! 

Myungsoo

First Impressions

Because of Jiyoon's connection to the soccer team via his platonic soulmate Sewoon, the former has already had the honor of meeting Myungsoo so it's a pleasant surprise to see him joining the Ghost Club as well. Jiyoon's impression of Myungsoo is that the older is easygoing, confident, and fun which can explain why their friendship grows to probably be one of the most entertaining pairs in the organization, and together, they're practically the "Dumb and Dumber" among the members. 

What's even better, as Jiyoon comes to find, is that Myungsoo is just as excited to jump right into the action rather than lounge around and take the slow-and-steady approach towards things. Together, they're a loud force to be reckon with which probably frustrates or annoys some of the others to no end, but Jiyoon's original goal for joining in the first place is to have a good time, and he's glad someone like Myungsoo is here to help him achieve that.

Hyejin

First Impressions

Jiyoon has always been someone easily fascinated by tales and stories, so it's no wonder why he was quick to ask Hyejin how life in London was before her arrival to Busan. While they did not become close extremely quickly as he did with Myungsoo and Seojun, Jiyoon doesn't clash with her at all, instead taking the initiative to help her feel welcome both to Moon High and to the Ghost Club.

Even better, Hyejin originates from Seoul as well, which adds to why he feels like she understands the struggles and complications of moving from place to place. Usually, it's in passing comments though because Jiyoon is naturally happy-go-lucky rather than angsty or anything of that sort, but if that helps Hyejin feel more included at school, he's happy to help anytime.

Final Thoughts?

Not much more to add, you've got the details down and I was glad to  be able to collaborate with everyone! Thanks for considering Jiyoon as a possible love interest for Sanghyuk, and I'll be looking forward to the first chapter of the story!