Well, I went to the Dear Friends concert in Hartford, Conneticut last Friday (May 20th).
I'll (hopefully) post a more complete rundown sometime later, but, for now, this'll have to do.
I only saw five people in costume there, including one guy dressed up as Sephiroth (of course) but I think someone mentioned that there was another up in the balcony.
I had seats three rows in, so I was really close to the orchestra.
Music was great. It's really something to hear the music originally heard via a console being played live by a full orchestra.
I'll update this to be more useful ... later.