As usual from you SG, a very good post, but I still think the leprechaun and fairy analogies are a bit of a stretch. I'm convinced that people who have come to agnosticism have not come to it believing a bearded, harp-playing guy on a cloud should be given equal standing with advanced physics. It's not that agnostics hold out for such fantasies, either. For me, it's the simple fact that we don't know if this universe was created by an unknown entity, some sort of natural scientific system, or just plain randomness. Defining some weird creator entity as a deity/god worthy of worship is a semantic battle I don't want to get into, and one that this discussion can do without, IMO.
There are many points of view of both atheism and agnosticism.
We can talk about two flavors of agnostics here to simplify the discussion. One flavor is the agnostic who is really an atheist but thinks of the god question as, you can't
prove gods don't exist so science doesn't allow you to say with certainty, there are no gods.
The second flavor is the one you are describing, the agnostic who feels 'gods' (usually one god because that is the common god belief in this part of the world) is a legitimate hypothesis for the origination of the Universe.
My earlier answer addresses both but in two different ways.
For the first flavor agnostic, I say, shift paradigms from asking, can you prove gods don't exist to the more appropriate question, what does the evidence tell us about gods? Proving gods don't exist starts with a conclusion, gods might exist, and asks the question, does any evidence fit this conclusion? I prefer to start with the question, where does the evidence about gods lead? It leads very clearly to the conclusion, gods are fictional beings.
The flavor agnostic you are describing assumes facts not in evidence. Once you follow the evidence and conclude gods are fictional beings, what evidence is left that one might consider gods as a viable explanation for the origin of the Universe? On what evidence do you add gods to your list of potential hypotheses?
Can you rule out Harry Potter or fairies or Leprechauns as potential explanations for the origin of the Universe? You can see, I hope, that adding willy nilly explanations, just because someone can imagine such origins, does not yield a valid hypothesis. On what basis do you add the god hypothesis to your list of possible Universe origins?
Have you considered the evidence based fact that all god hypotheses to date, where we have discovered the nature of some phenomena, have been failed hypotheses? Yet you want to continue considering the god hypothesis. How does limiting the god hypothesis to only the 'big' question, the origin of the Universe, offer any more potential to be the correct hypothesis than any other god of the gaps hypotheses which we know have all failed in the past?
And I haven't even gotten to the usual argument, adding a god layer is akin to invoking, "magic did it" which does nothing to increase our understanding of the Universe. How did the gods originate? It's a self defeating line of inquiry unless you have some evidence gods exist. And if you had such evidence, then we'd have the answer to how the Universe originated, but we'd need to start asking where did the gods originate?
I also think that religion has limited the perspective of many atheists. When contemplating something as unknown as the creation of our universe, many atheists are only able to see non-atheist veiwpoints through the lens of religions like Christianity or Islam. Like by saying "I don't know," we're somehow entertaining the possibility that angels and demons exist? Or by saying, "science hasn't yielded that information yet," I somehow all the sudden believe that bigfoot and pixies might be real?

I disagree.
This is a straw man as far as my conclusions are concerned. Show me any evidence of gods, any whatsoever, that does not come from god fiction. There is none that I am aware of. Because we don't know how the Universe originated, you are suggesting we include 'god magic' in the list of hypotheses. You don't have a single shred of evidence suggesting god magic, and all the god of the gap hypotheses to date have been failed hypotheses. Not to mention we know gods are fictional beings.
It would seem to me it is time to shelve the god hypothesis once and for all.