I don't see why it has to be some musical act every year. Do some variety! Have a magic act (Penn & Teller?), a puppet show, a stand up comic, etc. Those things would probably cost less, too.
Haul out a stage with props and have the cast of Seinfeld do a live “episode” of their old show. lol. Hey, its New York (well, not really but they act like it is)