This thread is intended as a peace offering, following a discussion of the allegory of the tower that got nowhere but grumpiness. But I would not post this just for the sake of peace. Rather, my recent research has prompted me to reconsider in a much more sympathetic light your readings of Bombadil and Goldberry.
There is a fundamental difference in the ways that you and I read Tolkien's texts. Like most people, you read the published text, the canonical version, while I read the texts biographically, attempting to situate them in relation to the development of Tolkien's thought over time. Both methods are legitimate but on occasion my approach prompts me to question canonical readings. In the case of my reading of your Bombadil research this was the case but has now swung completely the other way. I will explain.
In the following I will not provide references to sources, although obviously this is the foundation of my research. But time is limited. So below I will simply summarize and gesture to the sources and invite you to challenge me to explain my reasoning further and/or demand this or that particular source as you wish.
1. Initial conception of the Bombadil story
(a) Just a few days before commencing a new Hobbit story, Tolkien sends to Stanley Unwin a copy of the 1934 poem 'The Adventures of Tom Bombadil' and wonders if Tom might be made the hero of a new story.
(b) The very first notes for the new Hobbit story posit adventures in the Old Forest and with a Barrow-wight and Tom Bombadil coming in. An imagination of some form of these adventures predates the placing of the magic ring of the Necromancer at the center of the new story.
(c) So, when in mid-February 1938 Tolkien begins a second chapter (the first being the long-expected party) his only idea is that this chapter will take three Hobbits across the Shire to Buckland, which borders the Old Forest, so that a third chapter will tell of the adventures in Bombadil's realm.
(d) In general, Tolkien's idea is to write a sequel to The Hobbit of about the same length as the original but with most of the adventures happening before Rivendell. In late 1939, with the narrative hardly advanced beyond Rivendell, he writes to Unwin that his story is 3/4 complete. Hence, in the original idea of a sequel, Bombadil is not marginal (as he becomes) but a core part of the adventure.
(e) To understand this original vision one must look at the map of Wilderland in The Hobbit, in which the Wild only begins after the Last Homely House. In the first (then only) edition of The Hobbit it is said that the lands between Bag-end and Rivendell are gentle and respectable (the three Trolls have wandered down from the mountains, where the Wild properly begins).
(f) The new Hobbit story with 3/4 of the adventures set before Rivendell thus entails not only filling in the map before Rivendell but also telling a different kind of adventure. Tolkien's solution is to imagine these lands as not 'wild' but 'queer', with the meaning of 'queer' illustrated by the dream-like enchantment of the Withywindle valley.
2. Unpremediated Ringwraiths
One night out from Bag-end something unexpected happens. The very first draft tells how the Hobbits hide at the sound of a horse, the horse comes into view, the rider sniffs – and is discovered to be Gandalf. We now see Tolkien revise his prose so that on the horse is a Black Rider. After a second Black Rider appears the company of Elves turns up and they explain that these Black Riders are Ringwraiths. In a letter of March 1938 Tolkien describes this as an 'unpremeditated turn' to his story. The story that we know begins with this turn.
3. Composition of Bombadil story
Tolkien continues to write and gets the Hobbits to the house at Crickhollow, all ready to enter the Old Forest and commence the already planned 'queer' adventure in the realm of Bombadil. The date is now early March 1938 and Tolkien puts the story away until August. When he resumes writing in August he rapidly pens the adventures in Bombadil's realm, almost exactly as we read them today. Of course, there are a few later revisions, such as the idea (which halfir made much of) that Tom will not step beyond his borders and the dropping of Bombadil's self-designation of 'aborigine', replaced with the 'who are you, alone, yourself, and nameless'. But in general, what we read today is what Tolkien put down on paper in August 1938. No other section of what became Fellowship contains so little subsequent revision.
4. Bombadil in relation to the story about the Necromancer's magic ring
By August the main story about the magic ring has become central and so Bombadil is worked up out of the 1934 poem in a manner that is not only 'queer' but also complements this main story. At this point, Tolkien has the idea that humor and not taking life too seriously is an antidote to the evil magic of the ring, and Bingo Bolger-Baggins, the original heir of Bilbo, is a prankster Hobbit. The story at this time has Bingo host the long-expected party, and his vanishing from his own birthday party is the first of his practical jokes with the ring. He performs another practical joke in the house of Farmer Maggot. But Bombadil is a sort of fairy-tale ideal of not taking life too seriously and so while the ring of the Necromancer has no effect on him he shows up the limitations of a Hobbit's practical jokes – seeing Bingo when he puts on the ring and preparing the scene for Bree where Bingo falls off the table and vanishes and what looks like a practical joke isn’t.
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The above is pretty much what I had worked out a few years ago and is what has made me hesitant about accepting your in-depth readings of Tom and Goldberry, which seemed to me to read from a post-LotR perspective (in which Tolkien looks at the whole universe and everything in it) what was really a Hobbit kind of story, brilliant as is anything written by Tolkien, but far less ambitious than your research presupposes.
But in these last few months I've added another element to this biographical account of Tolkien's imagination of the story, and this has radically changed the resulting picture.
This new strand of research begins with The Lost Road, volume 5 of the Home series, which gives Tolkien's work just before commencing LotR. Introducing 'The Fall of Númenor' Christopher Tolkien quotes a letter by his father that states that only some while after composing the myth of Númenor did he integrate it into his mythology. Christopher declares that his father must have erred in his recollections, but his reading of the letter may be faulted. And then later in this volume Christopher expresses surprise that the conclusion of the 'Quenta Silmarillion', while evidently penned after composition of the myth of Númenor, makes no reference to it. The conclusion is obviously that Christopher has erred here and that his father's memory was correct. And this opens the question of when Tolkien did in fact decide to integrate Númenor into his mythology.
The answer is that this decision was made between March and August 1938, i.e. in the first break from composition of the new Hobbit story. The first explicit reference to 'The Fall of Númenor' is on the way to Weathertop, when Trotter says that Elendil and Gilgalad made a fort on this hill in the days of the Last Alliance. But actually the very first sign of the integration is in the house of Bombadil, who declares that he was here 'before the seas were bent'.
At this point one should step back and reflect on what is now before us. Back in February 1938 we have the 'Quenta Silmarillion' and we have a new Hobbit story that is set vaguely in days after the War of Wrath (this date established by Gildor's introduction in the Woody End), while Númenor belongs to a separate project. In August, when Tom declares that he was in the world before it was made round, we glimpse, for the very first time, Tolkien's vision of Three Ages of Middle-earth.
Why Tolkien hit upon this massive expansion of his mythology to encompass three ages is another question, which I will not go into here. What matters here is that the evidence (imo) points unambiguously to the vision of Three Ages of Middle-earth arising in Spring/Summer of 1938, with the adventures in Bombadil's realm the first thing that Tolkien wrote with this new vision in mind.
From this perspective, the adventures in Bombadil's realm bear witness to Tolkien's vision of a mythology that for the first time encompasses the vast and comprehensive ideas that are today regarded as canonical. Once Tolkien has hit upon this massive temporal expansion of his mythology sometime during his break in composition we can be sure that all sorts of ideas are now swirling around in his head.
Hence, with this discovery I find myself all of a sudden much more amenable to your readings of Bombadil and Goldberry. Intuitively, they make much more sense than they did hitherto.