There is already back arrow button at some screens, like MC profile. There is no need in looking for other buttons, it's suitable for any screens.
Not really required because there should be no case where this fails cause you cover all the bases with choices. Also choice([]) is a crash so it would fail with a crash before that anyhow.
Well, it means that the function cannot be used for teams with more than 4 characters of the same MPTrait, because there won't be enough lines for them
I don't think we'll even have more than 4 party members though, so it's probably fine.