Nice review. I wouldn't have been able to read it myself. How about this for an answer to argument 3:

Stefan's problem is his understanding of omniscience. A god who predetermines everything cannot really be all powerful, but predetermination isn't necessary for omniscience. Predetermination assumes no free will beings, and actually no free will at all for anyone other than the god. If there is free will, there is no predetermination, which most Calvinists would agree with.

However, we if we do have free will, how could God be Omniscient? He is because He knows every possible outcome of every decision by every free will being in every situation. He would have to know the possible outcome of every decision in all our lives, and how they would all shape the future like The Butterfly Effect. That's actually quite a bit more impressive if you think about it, as it requires an infinitely greater degree of knowledge.

He is still Omnipotent, however, because He still has the power to intervene as and when He sees fit. This does imply that humans do not have unrestricted free will, however. But really, the very idea of miracles means that we don't have unrestricted free will.

Overall, from the quotes you posted, it looks like Stefan has a specific idea of a god that he doesn't believe in. It's not the concept itself, it is his understanding of the Christian God. I suspect he has a negative history with Christianity, or people calling themselves Christian, or his misunderstandings of what was being said. Did you get the impression from the book that he had any knowledge of, or beef with any other major religion, like Islam, or Hinduism?