Wouldn't surprise me if it was Taemin. SM seem to really like their dancers when it comes to SHINee and Suju. Not to mention Tae probably has the biggest tween demand.
Suddenly it makes a little sense why they randomly threw Taemin on Henry's debut solo song. Probably like a trial run to see if he could handle doing the solo thing.
they're working on it! In 2020 I believe they will be able to give a decent live performance 
