Is it the track me and grunty were suspecting or different one ?
Not sure which track did you mention. You mean the OP for Lord El Melloi? Its melody is the one in the first trailer and I think it's that track at the end of Ep.0. But the song sounds quite different...dunno it's because it's the live version or it's really a different song with the same main melody.
If you talked about which tracks from SAO did they perform today, they're just Moon and Shadow and Aerial Fight.
Quite surprised that Remi covered so many songs originally sung by other vocalists, including Heigen, El Cazador, Mezame, and I told Kuga that Grunty must be over the cloud for this choice - they have Red Rose for the Encore.
She arranged it in the way that almost every musician got their solo parts. So I guess that they'll perform it again tomorrow, but don't know about the non-instrumental lives. It contains the solo parts of Violin, Guitar, Percussion, Flute, Accordian, Trumpet*, and Uilleann pipe. (Trumpet* was played by the cellist. The crowd went crazy over it. Such a big twist!)
*edited