The Frostfell - Fireworks quest says to "Loot 4 Ak'anon Skylighters from Nagafen's Lair". After blowing up monsters there for a while I got no fireworks to show for it. It makes me wonder if they aren't dropping because of the same type of bug that was in the Frostfell - Saving Santugg quest (info found here). If it is bugged, I assume it wouldn't fixed until the January patch ... (after the quest is normally over.) If someone has been able to get the fireworks to drop, any info would be appreciated.
Had the same thing happen in Blackburrow and Upper Guk. After mobs respawned they had the fireworks on them.
There are quite a few bugs with the Frostfell line of quests currently. Report them in the bug thread for the latest patch.