Is Icelandic Elf-belief properly basic

Yes! I'm an equal opportunity Reformed epistemologist.

Is belief in God properly basic, at least for some of us?

One way of looking at this issue is to try to determine who, in the question of God, has the burden of proof. A good many discussions in introductory philosophy classes presuppose that the theist has the burden of proof.

But is this correct? Are we better of just saying what my philosophy professor at ASU once said, that "you have the right to believe what you already believe, unless there is good evidence to support believing something different."

Does rationality involve neutralizing our prior convictions and starting from scratch? Why should we be expected to do that with respect to the question of God when we are not expected to do that with other beliefs. At least, when people have tried to this, not with respect to belief in God, but with beliefs generally (i. e. Descartes and classical empiricism), it has resulted in all sorts of beliefs (moral beliefs, the belief in an external world, the belief that the future will resemble the past, etc.) are unjustified, that most of us take to be justified.

Russell's Teapot and the Great Pumpkin objection

This links to an Russell's essay "Is there a God."

Many orthodox people speak as though it were the business of skeptics to disprove received dogmas rather than of dogmatists to prove them. This is, of course, a mistake. If I were to suggest that between the Earth and Mars there is a china teapot revolving about the sun in an elliptical orbit, nobody would be able to disprove my assertion provided I were careful to add that the teapot is too small to be revealed even by our most powerful telescopes. But if I were to go on to say that, since my assertion cannot be disproved, it is intolerable presumption on the part of human reason to doubt it, I should rightly be thought to be talking nonsense. If, however, the existence of such a teapot were affirmed in ancient books, taught as the sacred truth every Sunday, and instilled into the minds of children at school, hesitation to believe in its existence would become a mark of eccentricity and entitle the doubter to the attentions of the psychiatrist in an enlightened age or of the Inquisitor in an earlier time.

From Russell's essay "Is there a God."

The context here seems to be in establishing the burden of proof in debate about God. That debate, over the past few decades, has centered around Alvin Plantinga's controversial claim that belief in the existence of God can be properly basic, and in that context, the Teapot objection is known as the Great Pumpkin Objection. It is a strong, or as weak, as the Great Pumpkin objection to the proper basicality of theism.

This is a paper on the proper basicality debate.