1.
C onspiracy - If three (3) is company, then what is five (4)?
2. - Twixt dark below and dark above, below & between.
3. - + 60, -10, still stepping out of the same door.
4. - A place of first meetings, lingering glances, and (nearly) last farewells.
5. - Twenty-second in the line.
6. - A bit sweet, but backward, and if I gave a direct clue it would probably be crude.
7. - Elvish ... and a trio of Beornings.
8. - Gondor calls, "The flaming cursor!"
9. - Not new, not two, not race, not safe.
10. - They could make almost a Hobbit sequel, but Warwick is necessary first.
11. - With a name, he's a stalker above all others; without his name, sing who he is.
12. - Left behind; his namesake is on the Barrow-downs though.
13. - Scrambled in an anagram: retained in the taproom.
14. - Singular, lost in Ladros, in a house by the river.
15. - Bilbo passed, and the Age removed
16. - Before they were grey, they served still.
The Conspiracy (in Chapter 5) has four members: Sam, Merry, Pippin, and Fredegar Bolger, poor neglected chap.
For #3, you actually have the right door! But not the right answer.
And no on Bree or the password.
hS