Only addressing your last question here, about what hope the Elves find in the
coming of Men. Certainly, I think they see that they have a somewhat
better chance in the war against Morgoth with additional people on their
side. I don't know what the various Elves think their chances are against
Morgoth at this point in the story, but one always rejoices in good fortune
upon finding it.
But I think it does go further than just the immediate issue of the war against
Morgoth; some of my ideas here were also present in my earlier post this
week. The Elves know that Men are the Secondborn of Iluvatar, and that
both groups are part of one of Eru's great themes of Creation. Indeed,
they are part of that theme which is involved in turning evil to ultimate good,
however long that takes. The coming of Men, therefore, is surely a cause
for the ultimate hope, that of Arda Healed.
from the Arthrabeth Finrod ah Andreth (HoME X); Finrod speaks: This then, I
propound, was the errand of Men, not the followers, but the heirs and
fulfillers of all: to heal the Marring of Arda, already foreshadowed before
their devising; and to do more, as agents o fthe magnificence of Eru: to
enlarge the Music and surpass the Vision of the World! For that Arda
Healed shall not be Arda Unmarred, buta third thing and a greater, and yet the
same....And then suddenly I beheld as a vision Arda Remade; and there the Eldar
completed but not ended could abide in the present for ever, and there walk,
maybe, with the CHildren of Men, their deliverers, and sing to them such songs
as, evin in the Bliss beyond bliss, should make the green valleys ring and the
everlasting mountain-tops to throb like harps.
How's that for what the Elves hope
for?