Excellent topic, as always,
Esty!
In discussing Goldberry, we have to consider both the Bombadil verse and the LotR. The two present different views of her and of her spouse. It is almost as if the original verses represent an older folkloric tradition that has been overlaid by a later version.
I have in the past associated Goldberry (through my rpg character) with Uinen and Osse. The story of Ulmo's vassal who was tempted by Melkor and then returned to faithful following by the intervention of his wife Uinen has seemed to me to be more in keeping with the original tales of Tom's and Goldberry's nature. Osse has the power to make sea storms while Uinen calms them. I'm sure seastorms still existed in the Third Age, so I'm not sure if this particular power was still ascribed to the husband and wife of the waters even as Ulmo's power was said to be receeding.
As to the link through music, well, I wonder if we need to clarify what precisely was the original music of Arda. Was it a music of sound, as we normally associate the word, or was it rather a music of proportion, order, and measure? Music and the history of music is not really my balliwick, but I think that originally the word implied order and proportion without sound--the mathematical relationships of the universe. Yet Goldberry's "washing day" and the implied control over weather might imply some relationship less controlled and even, possibly, aligned with chaos? The female element in early folklore often pertains to elements outside human order.
Water is also a culturally derived signifier of cleansing--Goldberry's "washing day", to say nothing of the generations of women who wash their clothes in the waters of a river's edge, throughout human cultures--so that works against the chaotic element, unless, for example, the chaos of the drowning of Numenor is regarded as of just proportion and order.
just some random thoughts from Bethberry
