Sentience is certainly not fundamental in the way you describe it, so I agree with your points. I would however, argue that from my perspective as an "agnostic theist" when you look at the infinite or at least the "not appearing to be finite" universe, one cannot rule out the possibility of some greater sentient being (which we might perceive as a god). In fact if one accepts that the universe is infinite, the wouldn't some "greater" being have to exist? That being said, I really cannot fathom infinite. But I guess I just don't know....