I remember the street Melphomene as being spelled this way, and now it's spelled Melpomene. I know it's been changed over the years, and once you cross Dryades Street, which is now Oretha Castle Haley Boulevard, it becomes Martin Luther King Jr. Boulevard. Please help me out with this dilemma.
I am afraid you have misremembered. Architect, city surveyor and planner Barthelemy Lafon named the street in the first decade of the 19th century. It was named for one of the nine muses in Greek mythology, the others being Calliope, Urania, Euterpe, Thalia, Erato, Clio, Terpsichore, and Polyhymnia (sometimes spelled Polymnia, as on the streets of New Orleans).
I have heard some locals mispronounce Melpomene, putting in the extra "h" and calling it "Melf" for short. Perhaps these are the same folks who put the stress on the first syllables of Calliope and Terpsichore.
Part of Melpomene Avenue — the part between Earhart Boulevard and Baronne Street — was renamed in 1977 for the late Dr. King. In 1989, more of the street name was changed, this time from St. Charles Avenue to Baronne Street. The name honoring the Greek goddess was retained from St. Charles to the river.
It seems that everyone was happy with this arrangement. Dr. King and the Civil Rights movement as well as the history of New Orleans were appropriately recognized.