r/LOTRExtendedEdition

I've been doing some digging but this is the closest I've come up with as I see he either intentionally left it out, or wanted to include it but didn't get around to it. But what I see is that far into the Future, Melkor (Morgoth), will escape his chains where he’s been bound in the nameless void beyond the night. He will once again descend upon Arda (Middle Earth) and wreck havoc. The Battle to end all battles will begin called the “Dagor Dagorath.” All the Valar, Maiar, Elves, Men, and beasts (including the eagles) who did not fall to evil will fight against all of Melkor’s forces made up of Himself, the fallen Maiar (Balrogs and Sarumon etc…), Orcs, Trolls, dragons, fallen men, The 9 and their fell beasts. Melkor will lose this battle and finally be slain at the hands of a man called Turin son of Húrin. A Man who’s family had been cursed by Melkor in the first age to suffer one misfortune after another.  during this final battle Most if not all of Arda is destroyed. Then will come the Second music of the Ainor in which Arda will be remade. This time without Melkor’s interference in the music, Arda will be remade perfect. And that’s all we know for “sure” as not even the Valar know what that will be like, Only Eru.

I hear that Christopher Tolkien made an editorial decision not to include it. Can anyone confirm or expand or something?

To expand, I know Tolkien stated that nothing is evil in the beginning; even Sauron and Melkor were created "good." And I get that as beings with Eä (being/existence) given by Eru Ilúvatar, Maiar theoretically retain the agency to repent.

But still, is it theoretically still possible for redemption? Or is it not possible because maybe practically a Balrog’s pride and the depth of its "morgoth-element" (the spiritual stain of their master) make the choice to repent unthinkable to them.

Also.. If a Balrog did repent, would it lose its shadow and flame and return to being a 'bright' spirit, or is that physical form a permanent cage?