Oh yeah, there were all sorts of crazy cults, tons of gods that got absorbed from other religions as well as ideas like reincarnation, and worship of family deities too. And you have to remember too that these beliefs were spread out over centuries as well as well as the different Greek city states and then eventually the enormous Roman empire. So there's no real orthodox version of stuff.

I suppose the closest would be the Homeric versions of the Odyssey and Illiad (and Homer... he probably wasn't even one person - but an oral tradition passed down for generations until written down). Virgil's Aeneid (which was, heh, written as propaganda for Augustus Caesar, lol) was centuries later with an entirely different culture. So yeah, there's no real orthodoxy when it comes to their religion.