I heard that Flint was originally planned to allude to Jesus as being one of his pseudonyms, but that was dropped by censors due to its sacreligiosity. So they made him Lazarus instead, which kinda devalues one of Jesus's main miracles, since apparently he was just waking Flint up from a nap.
Later on, Jerome Bixby (the writer of "Requiem for Methuselah") picked up on this theme again in his screenplay "The Man From Earth." Perhaps he felt that by that time, it wouldn't be censored.
Kor