In The Year of the Flood, how does Adam One's explanation of creation and the fall of humanity compare to more standard Judeo-Christian ideas?

Margaret Atwood's The Year of the Flood is an interesting take on the creation and early biblical tales in Judeo-Christian beliefs.
In the story, humans essentially have the role of angels, messengers, and deities in a scientific setting. Adam One is the auspiciously benevolent ruler in control of everything, while other characters act as "God's Gardeners," a vegetarian sect who refuse meat but who are also literal gardeners who tend to "the entire world" by growing the essential plants everyone needs.
In the novel, it is prophesied that a "flood" will come to destroy the majority of humanity—like the biblical flood of Noah. However, this "flood" is actualized as an epidemic that quickly spreads throughout humanity, killing all but a few survivors (including the protagonists of the novel). In this way, the novel makes a more scientific interpretation of biblical events, painting them as natural cataclysms that result from human interference as opposed to God-ordained disastrous events.