The people in it are the actual 2004 actors and actresses from Avenue Q and Fiddler on the Roof.
From Playbill:
Avenue Jew, employed a mix of tunes from both musicals with revised lyrics by Randy Bobish, Rick Lyon, James Valletti, Stephanie D'Abruzzo, Molly Ephraim, Jordan Gelber and Melissa Bohon.
Wow. Just wow.
