* * Revised Fall of Gondolin pt.4 -- >end [the remaining sections] * *

[Maédhros]

From The People of Middle-Earth: Late Writtings:

It was intended to mean 'Golden-tressed', and was the name given to the heroic 'Gnome' (Ñoldo), a chieftain of Gondolin, who in the pass of Cristhorn ('Eagle-cleft') fought with a Balrog [> Demon], whom he slew at the cost of his own life.

and

More important: Glorfindel had sacrificed his life in defending the fugitives from the wreck of Gondolin against a Demon out of Thangorodrim,* and so enabling Tuor and Idril daughter of Turgon and their child Eärendil to escape, and seek refuge at the Mouths of Sirion.
* [In the margin, and written at the same time as the text, my father noted: 'The duel of Glorfindel and the Demon may need revision.']

Now the question is: What is a demon? What is a balrog?
I don't think that without a clear understanding of what exactly is a Demon we can proceed to make that change in The Fall of Gondolin.
I think that someone has suggested that we replace the hundreds of Balrogs to Boldogs.
I just don't think that with the change to demon, without anything specific we can proceed to such a change.
As for the revision of the battle of Glorfindel, we all know that JRRT was rewritting the entire Fall of Gondolin too.