[BUG] Dustwallow quests

During my questing in Dustwallow I've encountered a dreadful amount of bugged quests. Luckily, it's possible to make it through the zone, and exit at the intend level.
These are the quests:

1) Nat's Bargain
2) Spirits of Stonemaul
3) Corrosion Prevention
4) Survey Alcaz Island
5) Confirming the Suspicion (Either the quest has low drop rate, or they don't drop at all.)