Sep 20, 8:23am
For myself, I don't actually consider "Legolas" of Gondolin a character in Middle-earth.
Back in the very early Book of Lost Tales he was of the Noldoli, as well as the Elf Gimli, although in that conception "Legolas" was a Gnomish construction (there was no Sindarin in this early period), and it was even said that it may have been a confusion of the names Laigolas Legolast, which would have thus made these forms his true names (although granted, even a confusion can catch on and become a name, if "Legolas" is meant to be a form actually spoken to the character).
"Laigolas = green-leaf, (...) legolast i.e. keen-sight (...) but perhaps both were his names as the gnomes delighted to give similar sounding names of dissimilar meaning. Legolas, the ordinary form is a confusion of the two" JRRT Book of Lost Tales
This is interesting! But in any event, much much later Tolkien decided (edited a bit here, by me)
"Legolas means 'green-leaves', a woodland name -- dialectal form of pure Sindarin laegolas (...) (H.E. laica, S. laeg (seldom used, usually replaced by calen), woodland leg)."
So the name Legolas has become a dialectal Silvan name, suitable to Legolas of Greenwood. Was Tolkien going to retain this same name for an Elf of Gondolin? It's possible that he could have used the purer Sindarin form Laegolas here, but it's equally possible that Tolkien could have wholly avoided this and made up a new name for the Gondolin character, if he was to remain.
The name Glorfindel was also invented in Gnomish, but we know Tolkien decided to explain it (at least in WPP) as archaic in form (now in a Sindarin context), and that Glorfindel of Imladris was Glorfindel of Gondolin re-bodied, in any case.
Also, to be honest, I'm not sure I agree with JRRT when he writes (already quoted by you) . . .
"This repetition of so striking a name, though possible, would not be credible. No other major character in the Elvish legends as reported in The Silmarillion and The Lord of the Rings has a name born by another Elvish person of importance."
. . . in the sense that this would not be credible. And even if Glorfindel was considered archaic in form, to my mind it need not be updated for use in a later time.
Just my opinions here.
(This post was edited by Elthir on Sep 20, 8:27am)