TRAHALD: See him where the deer runs back and the alder wood begins.
HITHLAIN: This thing seems to lisp about where some random bloke has been supine!
EOMER: ‘Mere nothingness!’ He’s in Angst, sure, or turmoil at the least, but is he really such a nihilist?
T: Someone who complains when fasting will really come unstuck here.
WELLINGHALL: Here, a healthy water meadow meets Meduseld, perhaps.
ORTHANC: ‘Alternatively, be gracious here,’ we heard.
T: A bad experience with caviar in the North? Well, somewhere. It’s appalling.
O: A biblical dude and an Amsterdam bloom get together – cacophonously – to trumpet its presence!
W: Desire good opinion here, despite losing an article in transition?
EMYN MUIL: Here comes an equine hybrid carrying stoat furs? Sounds like it … pretty much.
ROHAN: Here, with a cruel, gloating shout, they ended the Maid of Orléans - give or take a couple of vowels.
SHAGRAT: Mixed rag hats are his style, perhaps?
Your logic for HITHLAIN is perfect. (You didn't mention the lisp, but I'm sure you took it into account).
For WELLINGHALL:
Healthy = WELL
A water meadow is an ING
Meduseld is indeed a HALL.
I suppose water that is 'welling' is moving and not stagnant, though, and thus healthy. I wasn't deliberately using the aqueously-connected meaning of well, though.
The only other correct element you have is WANT. But you need another element, and also to consider what 'in transition' means.
Well done on your correct answers so far.
However ...
C'mon! How many things could an Amsterdam bloom be?