I don't know if the parents knew it or not but Memphis was the name of a nymph from Greek mythology.
"In Greek mythology, Memphis was the wife to Epaphus, mother of Libya and sometimes the daughter of Nilus. She and her husband were the legendary founders of Memphis, which bears her name."
"MEMPHIS was the Naiad Nymph of the well or fountain of the Egyptian city of Memphis. She was a daughter of the
River Nile, who married Epaphos the founder king of her name-sake city."