Need Opinions!

So I came up with a great story Idea, it's gonna take place in Japan. The main character is the daughter of a wealthy family and she has a twin brother who attend this academy in Tokyo that's one of the best academy's in all of Asia, it has grades from Elementary - University. And there's dorms and what not. And this school is known for having student's from all of the world, mostly Asian of course. And this girl is obviously struggling from all the pressure her family gives her and etc.
My only problem is that, I originally wanted this to be a got7 fanfic with other cameo's.

But she's Japanese so that means her twin is as well.
So I wouldn't know who to make her brother from the idols, at first I wanted it to be Mark but i was like wait he's not Japanese.

** SO I have a few options I can do. ***

p.s the brother is more intelligent than her and more athletic. He's a still silly but usually quiet.

If you picked option one go ahead and throw names at me (with what group they're from or if they're solo so i can look em up easily) below in the comments!

1) choose a Japanese idol/celeb from Japan or from a Korean group to be the twin brother

2) just give him a Japanese name and make a fictional character no need to use a celebrity

3) plot twist; brother is actually adopted and is not actually Japanese