1. Plosive meets slithery thing (we hear) on Caradhras.
2. ABBA song swallows little Beatrice. It’s exhausting!
ORCS: Oo, they’re awful!
NEEKERBREEKERS: Cousins of Vogons? They torment with onomatopoeia!
5. Submerged stalker, or just a wet TV addict?
EMYN MUIL: Lovable rugby player loses surname and liquid, but gains an equine hybrid here, we hear!
AMON HEN: Grumble about chicken? Here?
8. ‘Lotsss of thisss in Mordor, my Preciouss!’ (he gasped).
9. Do this only for a taste of justice or a world of truth. (The twin of the last clue).
10. Nice place? No, a slum. Messed up.
NAZGUL: Breathing apparatus swallows map-book, in confusion. (They’re so bad at finding people, you’d think they had, too).
12. Terror of Cirith Ungol.
13. Morning marathon around (or rather up) here – and the final one.
14. To hear these might well dement. Perhaps they were played to Frodo in Cirith Ungol?
TREE-ROOTS: Much harder than feather-beds!
HOMELESSNESS: Hateful road brings epiphany of danger – and this.
ARAGORN'S SINGING: Beren and Luthien, brought to the camp-fire by this.
DEAD MARSHES: Inanimate bogs.
Nazgul is correct.
You need a different synonym for 'morning.'