The question is very hard to answer.
You see if we were to go back a few years, as in the time when Shakespeare was alive. Young boys used to play the role of the girl, because women were not aloud to at that time.
Now Junior or Jr, is known to describe a younger version of a person. Or a young person usually a boy.
Now lets think of Junior as young, but in Shakespeare's time. Would it be right for Junior to play the guys role? No...because people wouldn't see that as right.
So...think about it should Junior play the girls role, or play the guys role? If the guys role, then you choose. If the girls, then choose someone manly like JB.
(What I'm trying to say is, it would be better if you put Jinyoung down)