This refers to the east though, I believe that it refers to the fact that Cuivienen was destroyed and replaced by other lands.

Glad it was helpful!

It isn't very detailed, but we know that he was captured, so it's likely that Meaglin just told Morgoth. He may have played a little good cop/bad cop and asked what his greatest desire was.

He certainly made other places, like wherever it is that men go after they die.

I suppose one could see it that way, though with it all being a "mythological past" I always thought that if we accept this conceit, we accept that it happened already. Of course you and me and probably the author would agree that the modern world doesn't currently and never has looked like any sort of "Arda Healed" but at the same time it is just myth. I think the real issue with trying to discuss Dagor Dagorath is that it was left on the cutting room floor, so to speak. There's a few differing versions of it, none are very detailed (as prophecies usually are not) and usually just build upon the previous version here and there, adding or removing details. But according to Christopher Tolkien, his father abandoned the idea of Dagor Dagorath. It's hard for a lot of people to accept, as it's just a likeable idea, and the thought that there is a climactic and final end beyond the scope of The L.R. and it's appendices. One of the last versions seems to have morphed into the Andreth prophecy, making it "of man" rather than of Mandos - and this mentioned Túrin returning to fight Ancalagon, not Morgoth, leading some to believe this 'final battle' was The War of Wrath but of course we have no record of Túrin's spirit re-appearing there. Soooo, long story short, I don't know (sorry!)