This is so hard because beauty is subjective, and I find my character's pretty, but if i'm just talking about the world beauty standard:
Alicia is probably and 8, because she has a lot of scars, and those aren't considered attractive in most peoples' books.
Kattar: 10 out of 10. Except that he isn't that tall, so it would probably deduct him some points, depending on who you're talking to.
Jinwoo: 9. He's very attractive, and tall as well, but his odd mannerisms and way of talking would detract him charisma points in most people's books. As would walking around with a children's backpack like he always does.
Kimberly: sadly in the world's standard she probably wouldn't rank very high. a seven most likely, though imao, she's very pretty.