[Aiwendil]

NA-RG-32: I put a critical comma in the wrong place in my last suggestion. It should have been:

NA-RG-32{Flinding}[Fierce] he answered, and fear left him

. . . which I think sounds better than "answered he".

The spell: I suppose your reasoning makes sense. I am still a little unsure, but I can definitely see keeping the spell.

Further comments up to NA-RG-55

NA-RG-38: I agree with your use of "Fingon" in place of "Faery". But what do you make of the "seven kindreds"?

where sleep the swords of seven kindreds,

I am not sure whether this is a reference to some earlier conception of the divisions of Men or Elves.

NA-RG-40:

Thus NA-RG-40{Flinding}[the Friend] faltered, faintly stirring

I think we can just use:

Thus NA-RG-40{Flinding}[Gwindor] faltered, faintly stirring

NA-SL-08: I agree with the deletion, but in view of it I would not start a new sentence at line 1481:

There the twain enfolded phantom twilight {1475} and dim mazes dark, unholy NA-SL-08{, in Nan Dungorthin where nameless gods have shrouded shrines in shadows secret, more old than Morgoth or the ancient lords the golden Gods of the guarded West}. {1480} [B]but the ghostly dwellers of that grey valley

NA-RG-42: I would say:

NA-RG-42{Flinding}[Gwindor] fancied, fell, unwholesome

NA-RG-44: We might use "Gwindor" here instead of "fearful" but I'm undecided on which is to be preferred - saving the precise sense or saving the alliteration.

NA-SL-09:
We must of course delete the reference to fugitives from the battle, but your line does not have the requisite alliteration. All I can think of at the moment is:

NA-SL-09{that death and thraldom in the dreadful throes
of Nirnaith Ornoth, a number scanty, escaped unscathed.} Thence skirting wild [the wooded hills,]

There's a typo in line 1548 - "Nan-thatren" for "Nan-tathren".

NA-RG-51: This is a case where I'd go for "Elf" instead of "Noldo", leaving simple alliteration.

NA-RG-52: I would say:

Then NA-RG-52{Flinding}[Gwindor] fearful lest fresh madness

NA-RG-53:

NA-RG-53 {But Flinding the faithful}[The Faithful friend Gwindor] feared no longer;

If "friend" is considered a stress, then the first half-line is too long; if it's not, then it doesn't contribute to the alliterative scheme and is thus useless. So I would make it:

NA-RG-53 {But Flinding the faithful}[But faithful Gwindor ] feared no longer;

NA-RG-55: This can be:

and fared to NA-RG-55{Flinding}[Gwindor], and flung him down