Giants are certainly easy enough to prove as plausible.

And yes, I would agree with your assessment about most of them, but if you dig deeper, the first generations birthed things like the Titans and many of the little g gods, and then the demigods where the Rapheim. (I can never spell that correctly.) That mostly tracks with most mythologies I am aware of, like Tiemat birthing all sorts of monsters and being called something akin to the "Mother of all demons."