FF7 Rebirth Concert in Boston next week! What should I wear?

My husband and I are going to see the concert in Boston next week. What would you suggest wearing?

When we saw the Kingdom Hearts concert it was in July and warm enough for a casual Donald Duck cosplay for me (a sailor style blue dress with brass buttons with a red ribbon and yellow converse). My husband wore a polo with a subtle Mickey design.

Where it's still winter in Boston I can't really think of anything dressy but on theme! I'm a very casual fan of the game so I might be missing something obvious! I don't feel like it's a t-shirt and jeans thing though.

Help!