Maybe too late if you already decided, but I want to reply about my thoughts.
Firstly, I thought that all outfits fit Erik perfectly. However, I like #4 because of the uniqueness that brings him stand out and be memorable. #2 #3 are the classic choices that look good for him in the adult time. For #1, I would like to let him keep it for the royal ballroom or something like that.
So, as you said, if he's 16 and overwhelmingly creative, #4 is the suitable choice for me. (Unless you want to use the story that Eric let his mother guide, rather than expressing himself)
I'll wait to see your final result in the real event! 😊