Thanks for bringing that panel up, I always get fuzzy on gods and their origins! I don't necessarily see what you mean about creation though. Creation itself isn't godstuff, the matter of slain Elder Gods-turned-demons is, at least that's what I got out of that panel. The unconscious mind of man shaped the primordial godstuff remaining from an Elder God war into Skyfathers made in the image of man itself. They then had children with various manifestations of Gaea (producing Bast, Thor, etc.)
I don't see how within that system anyone can become a god just because people pray or think hard enough. It seems more like anyone can become a god if they have that spark of innate divinity, which will then be molded and given form by worshippers. I think in order to ascend/transform into a god, you need some inherent ties to the Elder Gods (whether it be direct descent or a genetic blessing).