Elros: Is he just a mixed up loser?
A: Material for a sailor’s headgear, inspired by Eighties pop icon?
Rian: Chaotic rain reveals her.
Elwing: Cattle sound changes vowel: spin and see her fly!
N: More agile blow in a whirl here.
D: Ancalagon’s brass instrument? A substance for a sailor’s weapon.
I: Sounds like a sick sailor, without hesitation. A lofty place, indeed.
Luthien: Makeshift dwelling and large river combine for a maiden.
Correct! Earendil is both password and theme. And I think you've answered your own question.
I know Luthien is only his grandmother-in-law, but I preferred it to another answer that was closer to Earendil but would only fit in backwards.