I think any pochette would be suitable for a special night at the opera/ballet. i would wear a wapity to a cool party or to dinner. the papillon seems a little big for a dressier event but I've seen it done in celeb pictures, what can't they get away with, lol, and especially it being a damier pap, that to me is a little dressier looking bec. of darker colors.
You're seeing "Hamlet" the ballet? That is the coolest! I absolutely love Hamlet. It is by far my favorite of Shakespeare's plays. A ballet would be so cool! I'm jealous!
I think the new Sophie bag would look great at the opera!