First, we'd need to really identify the "canonical" sources that constitute Greek mythology. (And do we include Roman sources in this? Do we need to distinguish between G-canon and R-canon?
The best sources (highest-level canon) are probably the archaic-period sources like the Iliad and Odyssey, along with Hesiod and all of the Homeric hymns, because they are the oldest sources and therefore "closest" to the mythological heroic age (which corresponds to the real-world Mycenaean era, back through mythological pre-history.)
Then we could have a "lesser canon", which includes the Greek playwrights, like Aeschylus and Euripides, along with other classical-era and Hellenistic sources. And finally, there's the Roman writers like Virgil and Ovid.
Ted C wrote:
I'm pretty sure that the creation of humans predates the birth of the Olympians in most accounts. Rhea kept Cronus from swallowing Zeus like his elder siblings and sent him to Crete to be raised.
There's conflicting accounts of how man/woman were created. According to Hesiod, Kronos created the first humans during the "Golden Age". The creation of woman, however, is often associated with the Prometheus story and Pandora. But I don't think there's anything in the literature that says the gods gain power by human worship. However, the gods obviously enjoy
human worship, and they are constantly appeased/placated by humans who promise to sacrifice X animals or whatever in their honor. There might be some echoes of Mesopotamian mythology with the idea that sacrificing animals to the gods was like "feeding" them - but this idea doesn't seem to be applied too literally, since most of the scenes on Olympus depict the gods feeding on ambrosia.