Matches: Dwarves have never taken to these.
Isildur's Bane: It betrays in the roundest manner.
Silmarils: Narnian prince begins to reside in hobbit dwellings? Such a mingling! See them shine!
C: Heavenly start to December contrives to shield a mariner’s sword.
Emerald: Leader in disarray gains a thousand: a jewel to adorn a steersman.
L: Lalaith in the dark land? Serves quarrellers right, some might say!
Lamps of the Valar: Objects of heavenly beings impersonating Miss Nightingale?
Arkenstone: Sounds like Noah’s vessel cast in granite! Resplendent thing.
Night of Naught: Day’s opposite becomes null, in song.
Years of the Trees: Happy days, and light ones.
Yes indeed! At one point in the story it says that Oin and Gloin have lost their tinder-boxes, (so incandescence clues for Gloin are doubly apt, although I didn't realise it at the time
) and then, in brackets, that 'Dwarves have never taken to matches even yet.' There are at least two other references to matches in Middle-earth ... Merry says just before the Scouring that the Shirefolk only need a match, and their rebellion will flare up (metaphorical), and Bilbo looks for his matches under the Misty Mountains and there aren't any (literal).
Doesn't seem to be a previous post, Mith (have checked again). But it doesn't matter now.
Just two clues to go. I gave a big hint for the Lalaith one upthread, and for the other one, I would resort to song.