Notes

HAZELOONA.

- Haseul just like I typed on previous answer is ESFJ. I can see how she becomes energized when she is with people. Her dominant function is Fe followed by Si. Haseul is the type who uses Fe to “read” the vibes of everyone in the room and is constantly keeping tabs on what everyone seems to be thinking and feeling. Then subconsciously takes in all this information, and make most of her choices based on this info, which essentially boils down to, “What can I do that will benefit the most people?” (The way she would never hesitate to let other members speak first, the way she would answer ot12 in every chance like fav episode just to show she's not thinking of herself and she wants the others to feel as happy as she is, to be included in the moments just like how she includes Yeojin as well). At the same time, the FeSi also uses mannerisms, expressions, emotions, and capabilities to influence and help others around her.
From what I see Haseul is also the type who most likely likes having a certain kind of cake on her birthday every year, prefer going on vacations to the places she always visited as a kid thanks to her Si function. Her Ne side tends to look on the bright side of things and enjoy unrealized possibilities, while her Si side keeps them grounded. That's why even when she faced ugly circumstances like in Iceland or Mixnine she would still tell herself there will be good things from this and she would still try her best in the future.
Although her Ti is inferior function, Haseul would still be able to think of complex theory when she puts her mind to it (this was shown in Loona tv when she discussed loonaverse, I'm pretty sure she uses Ti too when she is solving some problem where she think her Fe would not help).

- Heejin: ISFP

Her dominant Fi differs from Fe in that Fe is focused externally and is constantly asking, “How does the group feel about this?”, whereas Fi is focused internally and is constantly asking, “How do I feel about this?” FiSe’s also tend to hone in on one or two significant relationships that they naturally look for once their own needs are met—a partner, best friend, etc. They are highly protective of their ‘inner circle’. They will not hesitate to defend themselves or those they are close to when they feel attacked or threatened.

At their best, FiSe’s are great at knowing themselves, as they spend a lot of time on self-reflection. This is one of the reason why Heejin is great at improving (like in Mixnine when she was ranked in lower class she knows what she needs to fix and improve in order to show she can do better and move in better class).
She finds her own principles to be trustworthy and valuable, and can be inherently skeptical of that others try to impose on them, If something does not line up to her own beliefs, she cannot act in accordance with it. FiSe’s are typically very creative. Se likes very tangible, 5-senses (sight, touch, taste, smell, sound) experiences, so creating art with her hands (in Heejin's case: playing an instrument, painting, drawing, and doing handlettering) is very gratifying to her. Although her Te is inferior function I can see Heejin pulls out her troubleshooting skills when necessary to get a job done effectively. Though she can't multitask and might takes longer time.

- Yeojin I'm pretty sure is ESFP.
Yeojin lives in the moment, she especially feels that every moment should be spend on something worthwhile and fun, and doing anything she views as ‘work’ is arduous and tedious. She is all about having fun and experiencing new things, she wants to do things she wants to do. Yeojin is one of the funniest member in Loona, she has a very silly sense of humor, and enjoys pushing the bounds of humor to get people to laugh. She loves to be around people she can have fun with, and if someone regularly puts down her ideas for fun adventures, she might write that person off as “boring”. (I can picture Yeojin Hyunjin bicker over this but once they agree to do the same fun thing for example making fun of Haseul then they will get along well).

Chuu shares the same energy as Yeojin but I'm not sure whether she is also ESFP or not.

- Hyunjin is ISTP

The way Hyunjin takes decision is affected by Ti function a lot and it is strong enough for me to think Ti is her dominant function. Ti is primarily concerned with solving problems and finding answers, and often prides itself in its ability to be detached from situations in order to be as objective as possible. Ti types are more likely than others to be able to literally shut out emotions in order to be more objective. (Example: the incident when she chooses Heejin to change song in Mixnine, she thinks it's the best solution for Heejin and herself and she doesn't put their friendship in the way, she means well after all). Her Se makes her enjoy practical work that includes hand or body part hence she is good at sport, dance, but her Ni can make her easily bored (open folder: Hyunjin bored face meme). Also having Fe as inferior function I feel like this is very Hyunjin:

Their lack of interest in adhering to social norms and love of logic should not be interpreted to mean that they do not care about other people in their lives (in fact, Hyunjin can care a lot to those who mean something to her like Heejin and Haseul for example). They simply show that they care in a straightforward, problem-solving way (the way Hyunjin moves Heejin to other team, the way Hyunjin listens to Haseul's problems when she needs it the most despite her sometimes teasing her or insulting playfully). Many TiSe’s do care deeply about social issues and the welfare of their communities, they just don’t usually have the emotional stamina to be “touchy feely” with more than a handful of people who are close to them.

I wanted to type Gowon and Olivia Hye but I'm afraid I will mistype them so..