The 'Rebel Hangout' in high school story could be a place where the rebellious students gather. It might be a corner of the schoolyard, an abandoned classroom, or some other secluded area where they can be themselves, away from the more conformist parts of the school environment.
Silom is a well - known area for gay hangouts. There are lots of bars and cafes there. Another place could be Sukhumvit which also has some gay - friendly establishments.
Seashell Haven. The name makes you think of a place where seashells are abundant, perhaps a little beach shack or a cove filled with beautiful shells. It's a place where friends can gather and enjoy the seaside beauty.
Well, it could be about a group of artistic students who gather in a special corner of the high school, like an old art room. They share their sketches, talk about their favorite painters, and inspire each other to create better art.
It could be a story about the hangout experiences in high school related to prep (preparatory) activities. Maybe it's about students who are into prepping for college or some academic and social events, and their interactions during hangouts.
Maybe it's about a high school visit by a president. He could be interacting with students, perhaps giving an inspiring speech in the school hall, and then hanging out with some students who are interested in politics, sharing his own high school experiences.
Well, it could be about the various friendships and social interactions in high school. Maybe it's centered around a group of students who have a special 'hangout' spot in the school and the adventures they have there.
If there are unique characters in the artist hangout. For example, a really talented but shy painter who slowly comes out of his shell because of the positive environment. That would make it interesting.