The first two arguments are not arguments from ignorance, but arguments from well-founded empirical observations we all experience and upon which all our logic or systematic thinking is based upon. Besides, as the atheist I believe the onus would be upon you to provide a better explanation, rather than saying O well we don't know enough therefore I'm an atheist. By the way, the third argument is also a First Cause argument, in my opinion the best of the three, and all the arguments have to be taken together as one. Your refutation to the argument from degree, which is basically Descartes' ontological proof, is a completely false analogy. You say something to the effect that you don't need to know the ugliest person to say Sarah Jessica Parker is ugly. Another similar "refutation" is to say one can imagine the perfect island getaway, but it doesn't have to exist. Well, that is of course wrong, because implicit in the idea of perfection is existence. Therefore, that island is imperfect BECAUSE it doesn't exist, and the perfect island, just like the perfect being, would have to exist.
I'd really like to see a refutation to the contingent beings argument, seeing as it is irrefutable. God bless.