#1, #3, and #4, are, IMHO, examples of the futility of ontological or metaphysical arguments about the existence of God. There is no such thing as a provable ontology or metaphysic, hence any conclusions derived are totally hypothetical.
#2 is a tautology. The first cause could be the universe itself, matter, etc.
I agree with #5, although I probably wouldn't argue it in the same way that Aquinas would have.