My favorite bit regarding the Stranger's origin was in SWAMP THING, where Alan Moore implied that the origin he'd written was correct, in the following lovely dialogue with Etrigan, the Demon:
Stranger: Ah yes, Etrigan, the demon who fancies himself half a man.
Etrigan: "Oh kettle, thou art black!" the pot exclaims! I know one more ambivalent far than I... a lonely soul who, mentioning no names, will not choose 'twixt the sulfur and the sky. Who will not serve above, nor reign below, but walks a path 'twixt Moloch and the manger. Who do I speak of? Is it one we know? Or could I be referring to--