I'd never even read a MinSu before you mentioned that! I just read my first one and yeah, I can see how that might work... You've given me a lovely idea for a subplot, since Junsu already had a place in the story. There's no reason why he can't turn up a bit sooner and either catch Changmin's eye or make him jealous...
The main pairing will most likely be MinJae, with YunJae in the past. Sorry if that doesn't work for you. I usually write YunJae, but Changmin has really caught my imagination in the last few weeks and what the muse wants...