"He DID originate all of the Max Bialystock songs in THE PRODUCERS, but none were break-out songs that crossed over into 'standards' level (like "Defying Gravity" or "Popular" from WICKED, for example)"
Ok, like if we ask the average person on the streets, they are going to know the songs "Defying Gravity" or "Popular"???...I don't think so. If your teacher knows anything about Broadway, he/she will know some songs that Nathan has performed. I would also suggest "Hakuna Matata" or "King of Broadway" or "Betrayed" from The Producers. It is my understanding that in these kinds of classes, as long as you can support what you are writing about with facts, it is acceptable. A "famous' song is in the eyes of the beholder. Broadway audiences will know them, so they are familiar to someone.
The only review of a show that matters is your own.