Balin for B one.

DORA: Unlike at least two of her kinsmen, this one is most likely no explorer!
IRMO: Gardener and dream-keeper?
SAEROS: Elvish gob****e forced to go commando – and the rest.
YELLOW: The facial hue that Gollum dreads?
LOTHO: A guy with a salty wife starts to howl, revealing him.
LINDON: Find this fair place in a tunnel in Doncaster!
APPLE: Projectile fruit for a Breeland gob****e.
B A famous gravestone bears his name.
ISEN: It flows through Paris. It mingles and loses direction. Then it flows again.
C A warrior. But changed fully at his core, and flipped at either side of it, he is cruel no longer.

Nope.

Good idea, though.

Gorthaur comes to mind for C one.

Nothing to do with Gorthaur.

Then what does 'cruel' mean?

It means cruel. The clue is cryptic.

Celegorm?

Or just Ceorl, by changing the u in CRUEL to O, and rearranging the word?

No.

I (pretty much) always account for every letter in my clues.

No to which one?

That's more like it. And flipping the letters either side of the U.

DORA: Unlike at least two of her kinsmen, this one is most likely no explorer!
IRMO: Gardener and dream-keeper?
SAEROS: Elvish gob****e forced to go commando – and the rest.
YELLOW: The facial hue that Gollum dreads?
LOTHO: A guy with a salty wife starts to howl, revealing him.
LINDON: Find this fair place in a tunnel in Doncaster!
APPLE: Projectile fruit for a Breeland gob****e.
B A famous gravestone bears his name.
ISEN: It flows through Paris. It mingles and loses direction. Then it flows again.
CEORL: A warrior. But changed fully at his core, and flipped at either side of it, he is cruel no longer.

B is Bob?

No.

Barrow?

No.

It's a name that appears on a gravestone.

Which one? A real-life one?

Could be.

Beleg?

No.

I am out, then.

You were warm when you said 'real life.'

Oh.

Oh

It just dawned on me. It was right there the whole time!

Beren.

DORA: Unlike at least two of her kinsmen, this one is most likely no explorer!
IRMO: Gardener and dream-keeper?
SAEROS: Elvish gob****e forced to go commando – and the rest.
YELLOW: The facial hue that Gollum dreads?
LOTHO: A guy with a salty wife starts to howl, revealing him.
LINDON: Find this fair place in a tunnel in Doncaster!
APPLE: Projectile fruit for a Breeland gob****e.
BEREN: A famous gravestone bears his name.
ISEN: It flows through Paris. It mingles and loses direction. Then it flows again.
CEORL: A warrior. But changed fully at his core, and flipped at either side of it, he is cruel no longer.

Indeed! Well done. And over to you!

Well, I've managed to come up with this.

1. Son of the one called crafty.
2. [Name], son of...
3. One of leaf-droppers
4. A messenger.
5. ...[Name]
6. A villain by another title
7. Used to deceive her spouse by the one above.
8. One of the four that 'bow to no one'.

Hope you like it!

(P.S: I am not sure 7 fits the theme, but the text implies she does.)

3. Pippin?

1. Maeglin / Lomion?

1. Son of the one called crafty.
2. [Name], son of...
PIPPIN: One of leaf-droppers
4. A messenger.
5. ...[Name]
6. A villain by another title
7. Used to deceive her spouse by the one above.
8. One of the four that 'bow to no one'.

Maeglin does fit the theme, too, but I couldn't make him fit all the letters.

6. Enemy?

Nope. It's a more...obscure title.

7. Eilinel?

6. Bauglir?

1. Son of the one called crafty.
2. [Name], son of...
PIPPIN: One of leaf-droppers
4. A messenger.
5. ...[Name]
6. A villain by another title
EILINEL: Used to deceive her spouse by the one above.
8. One of the four that 'bow to no one'.

Not Morgoth. The other villain. The one who used Eilinel directly.

Password: CAPTIVES?

If so, Sam for the last one.

Or maybe CAPTURED?

Or CAPTURES?

Pervinca nails it again
 

C: Son of the one called crafty.
A: [Name], son of...
PIPPIN: One of leaf-droppers
T: A messenger.
U ...[Name]
R: A villain by another title
EILINEL: Used to deceive her spouse by the one above.
D: One of the four that 'bow to no one'.

1. Celebrimbor, son of Curufin? Both crafty and craftsy.

Oh, and A/U must be AGARWAEN, son of UMARTH.

CELEBRIMBOR: Son of the one called crafty.
AGARWAEN: [Name], son of...
PIPPIN: One of leaf-droppers
T: A messenger.
UMARTH: ...[Name]
R: A villain by another title
EILINEL: Used to deceive her spouse by the one above.
D: One of the four that 'bow to no one'.

DAUR for D?

CELEBRIMBOR: Son of the one called crafty.
AGARWAEN: [Name], son of...
PIPPIN: One of leaf-droppers
T: A messenger.
UMARTH: ...[Name]
R: A villain by another title
EILINEL: Used to deceive her spouse by the one above.
DAUR: One of the four that 'bow to no one'.

RINGLORD for R?

Could T be THRAIN? He passes on a map and a key, and maybe a message too.

CELEBRIMBOR: Son of the one called crafty.
AGARWAEN: [Name], son of...
PIPPIN: One of leaf-droppers
T: A messenger.
UMARTH: ...[Name]
RINGLORD: A villain by another title
EILINEL: Used to deceive her spouse by the one above.
DAUR: One of the four that 'bow to no one'.