In Greek myth, Eurydice was the wife of the musican Orpheus. When she died, Orpheus was given permission to travel to the underworld to find her. He was allowed to lead her back to the world of the living on the condition that he didn't look around to see her following him until they left Hades. However, just as they were leaving, he succumbed to temptation and looked around, and she vanished back into the world of the dead.
The Valse des Roses is a traditional French song usually played on the accordion. Similarly, The Pauvre Fou by Tagliafico is a more popularist work than Swann's highbrow taste.
La Reine Topaze is an 1856 opera by Victor Massé (1822-1884) a French composer who wrote twenty operas.
Serge Panine was a bestselling novel by Georges Ohnet (1848-1918), adapted into a play which was not a critical success. Swann, again, is indulging Odette's taste for more popularist work. Olivier Métra (1830-1889) was a composer and conductor. His music was extremely popular, and he conducted at the Folies Bergère. Reynaldo Hahn, a composer who was Proust's close friend and lover, featured some of Métra's waltzes in his own work.