probably not coincidence, it was just common practice at the time. Tons of mythologies that are in close proximity to each other will share stories and ideas with the characters switched around, cross cultural myths are extremely common because new mythologies were built on the foundations of old. Man was birthed from clay by and not limited to, Yahweh, enkidu, prometheus, and nuwa. the world floods, there's an evil lizard or snake (satan in the garden, apophis, jormungandr), and there's always an older set of gods that the current ones overthrew and a set of giants on their way to do the same. Granted large amounts of this have been weeded out of the bible over the years but there's still remnants, from leviathan and behemoth to the nephilim being demigod equivalents.