[ArcusCalion]

I actually found a few more things I wanted to comment on:

VE-13.04 <AB2 The waters of Sirion lay between the hosts; and long and bitterly they contested the passage. But at last [Eönwë] crossed Sirion and the hosts of Morgoth were driven as leaves, and the Balrogs were utterly destroyed> <BT, save VE-13.045 {some few that}they fled and hid themselves in caverns inaccessible at the roots of the earth> , <AB1 and Morgoth[‘s army] fled to Angband pursued by the hosts of [Eönwë].

why the removal of some few? replacing it with "they" is grammatically incorrect, and the use of the plural doesnt change the implication that several Balrog's hid themselves in the earth.

Then Men, such as had not perished in the ruin of those days, fled far away, and it was long ere any came back over Eredlindon to the places where Beleriand had been.

should it be Ered-Lindon? just a format question i guess.

VE-19 Yet not all the Eldalië were willing to forsake the Hither Lands where they had long suffered and long dwelt; and some lingered many an age in the West and North, and especially in the western isles and in the Land of Leithien.

The Land of Leithien is used by Tolkien in his early conceptions of the history of the legendarium to describe the land that became England. In the later myths this geographical place was called Lindon, so should it be changed?

But Morgoth himself the {Gods}[Valar] thrust through the Door of Night into the Timeless Void, beyond the Walls of the World; and a guard is set for ever on that door, and {Eärendel}[Eärendil] keeps watch upon the ramparts of the sky.

I seemed to remember that in MT there's a footnote about the seeming inaccuracy of this statement in terms of even the flat earth cosmology. Tolkien remarks that it undoubtedly arises from the recording discrepancies of the Mannish scholars. I cannot at present find the quote, but would it be a good idea to include that as a footnote?