Adam and Eve? It has some biblical references of course, but the only thing from that particular story is when Crowley (still named 'Crawly' then) was talking to Aziraphale about where his flaming sword went.
See, "Earth's resident angel and demon" was the snake from the forbidden fruit tree, Crowley (He is "human" shaped form throughout most of the book however), and the angel guarding one of the gates to the Garden of Eden, Aziraphale (Who had a flaming sword, except he gave it too Adam and Eve 'coz they looked cold).
Erm...unless you clarify your summary of Lili...I'm not picking it up. Come on, it's book "recommendations"! Sell your book to us deprived readers! Or to this deprived reader if no one wants to be called "deprived".