The piazza crew didn't sing a song from the show. According to Playbill, they sang "Migratory V," which is apparently an Adam Guettel song. Adam Guettel sang with them, I think. It was a little weird that Victoria Clark and Kelli O'Hara were the only participants in the musical numbers put on by the shows who were also named in the program. I wonder why that was done -- their names would attract ticketbuyers, but so would Dan Fogler and Cheyenne Jackson and some other people who performed with their show who didn't get singled out.
Most (but not all) soloists just used a piano accompanist of their choosing, although Idina performed with a solo guitarist. Most of the performances by the musicals had more backup than just piano. The program card lists musicians playing bass, piano, percussion, keyboard, drums, and guitar, as well as a separate listing for Liza Minnelli's band.
Yes, Ben Vereen obviously enjoys the spotlight, but what performer doesn't? He didn't bother me at all. And he signed and posed for pictures for everyone who wanted them at the stage door and didn't leave until about 12:30, so good for him.
"What was the name of that cheese that I like?"
"you can't run away forever...but there's nothing wrong with getting a good head start"
"well I hope and I pray, that maybe someday, you'll walk in the room with my heart"