So I read it, and my take is somewhat different, likely just because of my starting point on such things.
To begin, I saw the objective of the article to substantiate the legitimacy of a belief in God, although not to prove the existence of God. That is, the inquiry was whether the epistemological standard a believer in God accepts is substantially similar to the one that the non-believer in God accepts in other matters.
Take, for example, what Plantiga accepts as a foundational belief: "I see a tree." He suggests that one's acceptance of the tree is foundational in that it requires no proof, but it is basic, and he suggests then that a belief in God is as well. According to this, we no more need to justify the tree's existence than we do God's, which would make the argument (in theistic terminology) that our acceptance of the tree's existence is no more or less an act of faith than is our belief in the existence in God.
My initial thought is that I'm not entirely convinced that our belief in the existence of a tree is foundational, at least not for Descartes (although the existence in God was ironically foundational to him, thus providing a basis for him for our knowledge there wasn't an evil genius manipulating our thoughts). "Foundational" therefore does not mean indubitable to Plantiga, nor does it mean fundamentally necessary for comprehension in some Kantian sense. I sense that his view of foundational is a form of pragmatism.
Regardless, Plantiga's question as I take it most generally is whether it is equally rational to accept God's existence as the tree's. The part of Plantiga's analysis not really discussed in this thread, which I took to be the crux of the counterargument against him, is that of the Great Pumpkin. That is, if I can say that God exists as a foundational belief, then why would I not be able to say the same of any absurd non-physical entity, like declaring there is a Great Pumpkin who visits us each Halloween and delivers us pumpkins.
The problem, as I see it, is that we're being asked a question without being provided a basic definition of what we're being asked to believe in. It seems clear that God as Plantiga envisions him is not the Great Pumpkin, so I'm left with the conclusion that the Great Pumpkin God is not a foundational belief, which means I don't know of the existence of the Great Pumpkin God like I do of the existence of trees. So, then, what sort of god would be foundational and just as rational a thing to believe in as a tree?
I think I can conclude that a god who parts seas and sends manna from heaven would be as absurd as one who delivers pumpkins, so that god wouldn't be foundational. If the god I'm being asked to accept as foundational is some nebulous, abstract, unknown entity that might have had a hand in our existence, then I guess that could be foundational, but if it's so ill defined, I'm not sure what the atheist is denying when he denies that existence either. So, should a Christian tell you that his view of the resurrection of Jesus Christ is as foundational as my view of the tree, I think that's nonsense and fails under the Great Pumpkin objection.
The question I don't think is answered adequately is what makes Yahweh (or Zeus or the Sun God or whoever), different from the Great Pumpkin? All of this is to say that I think the Great Pumpkin objection is not adequately responded to. So, to the question, "Is Belief in God Properly Basic?," a discussion of "basic" and "foundational" seem to put the cart before the horse if we don't know what God is.