CZJ lip-synced the entire song. Completely obvious. She didn't wear a mic. It was necessary to her because she agreed to dance. Good for her!
Hudson was the best part of the ceremony. Blew Adele, Streisand, et al out of the water (vocally).
"The Spectacle has, indeed, an emotional attraction of its own, but, of all the parts, it is the least artistic, and connected least with the art of poetry. For the power of Tragedy, we may be sure, is felt even apart from representation and actors. Besides, the production of spectacular effects depends more on the art of the stage machinist than on that of the poet."
--Aristotle