Nice.
@Inziladun
I love the Avatar. A Numenorean Faithful, hey

, who tried to stop the train wreck. He's as awesome as Silmarien always has been in my eye. What was his name in the Faithful's tradition as a 'Tar'? and have you read the stuff on the Caves of the Forgotten?
I think your post goes to the key differences in the metaphysical distinctions between Elves, mortals and Ringwraiths. I remember writing the post recalling that Gandalf did say, as you suggest, that it was Elves in the Blessed Realm who had that fearlessness towards Ringwraiths.
@Reader--thinking out loud
The exact 'how' the Elves in Valinor were able to change and access some kind of innate? capacity to enter the Fey/Spirit world is never explained. Was it the 'Light of Aman'? Is this about The Two Trees, or was this about proximity to the Valar? What on earth is the Light of Aman, anyway, I mean, what's it doing to Elven flesh? What happened to Frodo, Bilbo and Sam once they were immersed in the Light of Aman? Numenoreans were gifted with Life Extension by their proximity to Aman, weren't they? And did a Vala step on in and grant the Hobbits some kind of longevity? And how is an adaptation of the capacity to modify Mortal Men implied in the transition to Ringwraith, when a perverted Maia had modified this process?
The Elven Rings and what Galadriel did with Lothlorien (Frodo, for example, or was it Sam commented that the Seasons pass 'differently' in Lorien, not just an appreciation of 'time passing slowly', but some fundamental change in the effects of time on life's expression), imply that there are means of opening dimensions in Middle Earth to the same processes that modified the Elves when they became Eldar. I.e. rather than go to Aman, byo Aman-ising agent to Middle Earth, which is what Celebrimbor, Galadriel and co did to make life in Middle Earth more bearable for them, in their Banning or choice to remain.
So, I'm intuiting that the immortality Gifted to the Eldar could be extended, in a 'radiance' kind of idea, or 'girdle' thing--deliberately drawing on the term 'Girdle of Melian' where Doriath was an analogous effect, but of a Maia--which was what the Three achieved. Something Celebrimbor did when he made the Three meant that the Elvish body or Light of Aman or something of the First Age before the world was bent could be made that affected the very life of Mallorn in a very big area effect. It was the Elvish variation on what Sauron's presence did at the Dol Guldor in Mirkwood. What are these folk puttin' out?
Adapting from the last two paragraphs--the Nine Rings--appeared able to extend mortal life. I am wondering what the Eldar's intention was for that, were Sauron not to have perverted the Rings. I seem to remember that Celebrimbor and co
had a hand in the making of the Rings of Power beyond the Three. (Poor guy, he was hot for Galadriel and made the Elessar to try to woo her, in one take on the history. Was it just that he was not that good looking for an Elf? He never married and had kids and no-one ever explains why an Elf doesn't do that). What was the actual nature of the peril the One had for the wearers of the Three. We know the Three could communicate telepathically. But, what actually was the Elves' (not Sauron's) intention for the mortal form, for The Nine--before the Elves twigged who Annatar was--then when Sauron was detected speaking the Ring Spell at the Sammath Naur at Day Zero of the One. I suspect the Gwaith-i-mirdain knew how to extend the life of Men, almost infinitely!
What was meant by implication of the word "Ruling Ring" to the Three though? I don't think it ever meant the Elves were going to turn into Ring Wraiths. What I believe it meant was that Sauron forced open a communication conduit and could invade the minds of the wielder of the Elves. Sort of like the Palantiri hierarchy and all of that. Perhaps, though, Sauron could conceal the scrying, and invade the mind of the Elf, piece meal, or unawares, or during sleep? It's never really explained what the Ruling Ring could do to the Three, but it is--clearly--stated that the initial presence of Sauron when he forged the One, never really perverted the actual rings. The War of Elves and Sauron went on for many decades, after Celebrimbor's head was severed by Sauron and sent back to the Ost-In-Edhil on a pole, to terrify and do Sauron-y things to the Elves. Sauron amassed a big horde of evil armies at Tharbad, while the Numenoreans were on their way. The Three were then wielded for millennia with perfect fidelity to their cause, without taint.
Whatever happened to the One while Sauron was in Numenor. He had it by then, I seem to remember (this part of the history always gets muddled in my head)?
In any case, these items all imply something else about the nature of metaphysical influences in Middle Earth artefacts: there is some kind of energetic flow between beings in linked artefacts--as well as--flow or presence of actual will. Mind Meld, though, is only one part of the effects. When it comes to all that stuff about 'Secret Fire' and 'Shadows' and 'the Unseen', there is something else at work. I'm also thinking of Ungoliant here, who had Unlight in her webbings. It actually absorbed, or redirected light. Light could not actually exist or flow in her Cloak. This seems, also to be implicated in what Tolkien meant by the Shadow....