[Maédhros]

Come to think of it, whence derives the dialogue from QS77? I don't have all the books at hand, but I can't think of a source. Did Christopher invent it? If so, we might just drop it completely and follow the dialogue in TT.

I think that with the justification that Findegil provided, it think that it is safe to keep it, and for that I'm glad.

This piece is a bit problematic. I see the purpose of your changes: to alter it so that it is describing, in the pluperfect, what has just passed. But if it does so and nothing more I see no reason to keep it.

I think that we should make every effort to keep that line, and I think that Findegil provided a good reason for it to be done.

Here as in the TY it is Húrin who kills Mîm the traitor of Túrin. Thus it might be that Tolkien changed his mind on this topic after Q30. But I don't see it as such a easy thing to change, or do we simply go back to TT where Úrin kills Mîm for his behavior and without any other reason or do we put in some Sil77 material?

I think that we must make Húrin kill Mîm. If you see the whole part in the Wanderings of Húrin

Tuor weds Idril daughter of Turgon.
Húrin comes to Nargothrond and slays Mîm the petty-dwarf. He and his men carry off the treasure of Glaurung and bring it to Doriath. Húrin is admitted in pity.

At first I thought that it was only Húrin who came to Nargothrond, but I noticed that the next sentence has his men carry the treasure. I think that there is no doubt that this is the later idea of JRRT regarding this and we must be faithful to it.

I thought that it might be possible to add the part about Húrins admiration for Felagund, and the Information about the sons of Feanor and their reaction to the news. I would add them thus:

I really like this:

§1f (§271) RD-EX-05 <WH, Year 501 of The Grey Annals Of the wanderings of Húrin[ and his men] there is no tale told, until {he}they came at last late in {this}[the] year to Nargothrond. It is said that he had then gathered to him other fugitives and masterless men in the wild, and came south with a following of a hundred or more. But why it was that he went to Nargothrond is uncertain, save that so his doom and the fate of the Jewels led him. Some have said that maybe he knew not that Glaurung was dead, and hoped in his heart distraught to take vengeance on this evil thing - for Morgoth would conceal the death of Glaurung, if he could, both because the loss was a grief to him and a hurt to his pride, and because (from Húrin especially) he would conceal all that was most valiant or successful of Túrin's deeds. Yet this can scarce be so, since the death of Glaurung was so bound up with the death of his children and revelation of their evil case; while the rumour of the assault of Glaurung upon Brethil went far and wide. Certainly Morgoth fenced men in Hithlum, as he was able, and little news came to them of events in other lands; but so soon as Húrin passed southward or met any wanderers in the wild he would hear tidings of the battle in the ravine of Taeglin. More likely is it that he was drawn thither to discover news of Túrin; to {Brethil}[Doriath] he would not yet come{, nor to Doriath}.>RD-EX-05.5>WH /And of old /he had been an admirer of Felagund. RD-EX-06 <QS77 {and}They passed southwards down the ancient road that led to Nargothrond; and {he}they saw far off to the eastward the lonely height of Amon Rûdh, and Húrin knew what had befallen there. At length {he}they came to the banks of Narog, and ventured the passage of the wild river upon the fallen stones of the bridge, as Mablung of Doriath had ventured it before {him}them; and {he}they stood before the broken Doors of Felagund, Húrin leaning upon his staff.>

But there must be a way to include the fact that Húrin was given the dragon helm in Brethil.
So I would add this:

§1f (§271) RD-EX-05 <WH, Year 501 of The Grey Annals Of the wanderings of Húrin[ and his men] there is no tale told, until {he}they came at last late in {this}[the] year to Nargothrond. It is said that he had then gathered to him other fugitives and masterless men in the wild, and came south with a following of a hundred or more. But why it was that he went to Nargothrond is uncertain, save that so his doom and the fate of the Jewels led him. Some have said that maybe he knew not that Glaurung was dead, and hoped in his heart distraught to take vengeance on this evil thing - for Morgoth would conceal the death of Glaurung, if he could, both because the loss was a grief to him and a hurt to his pride, and because (from Húrin especially) he would conceal all that was most valiant or successful of Túrin's deeds. Yet this can scarce be so, since the death of Glaurung was so bound up with the death of his children and revelation of their evil case; while the rumour of the assault of Glaurung upon Brethil went far and wide. Certainly Morgoth fenced men in Hithlum, as he was able, and little news came to them of events in other lands; but so soon as Húrin passed southward or met any wanderers in the wild he would hear tidings of the battle in the ravine of Taeglin. More likely is it that he was drawn thither to discover news of Túrin; to {Brethil}[Doriath] he would not yet come{, nor to Doriath}.>RD-EX-05.5>WH / for while in Brethil he was given / the dragon-helm and of old /he had been an admirer of Felagund. RD-EX-06 <QS77 {and}They passed southwards down the ancient road that led to Nargothrond; and {he}they saw far off to the eastward the lonely height of Amon Rûdh, and Húrin knew what had befallen there. At length {he}they came to the banks of Narog, and ventured the passage of the wild river upon the fallen stones of the bridge, as Mablung of Doriath had ventured it before {him}them; and {he}they stood before the broken Doors of Felagund, Húrin leaning upon his staff.>