Those can be combined. But if the members are opposed to any of them I can leave them out.
Well, pretty simple plots which will more than likely evolve based on each member that joins.
Super Powers - Unlike adults with Super powers, teens are more likely to let their emotions and hormones get the best of them so there will be issues like people thinking of them as freaks, or will they be selfish or selfless with their powers. what happens when they get into a fight, with a super, a non-super, when authorities get involved.
School - The basics, sex, cliques, getting in trouble, and avoiding trouble. New students, annoying roommates, embarassing pranks. (If it's highschool then they'll live in a boarding school, college is of course dorms). Just to warn you, I do have one character who is a male but going through the process to become female. so "she" will end up rooming with a female, which could cause problems. And also be a good plot device to make things interesting.
Genderswap - Character gets taught a lesson in seeing how the opposite sex lives. one person will be the swapped character other members will play friends and rivals, and other people who know that character. depending on how many people join, there can be several swapped characters.
What other information would you like?
Plans are less specific with my group RPs, I have similar ideas in Solo as well.