DB/Quests: Fix The Nightmare Manifests / Hope Within the Emerald Nightmare / The Boon of Remulos / The Keeper's Favor/Walking Legend

Closes #10410
Closes #4902
Closes #10407
Closes #10406
DB/SAI: Script Witch Doctor Zum'rah

Closes #10404
DB/SAI: Meridith the Mermaiden

Closes #10418
DB/SAI: Free at last!

Closes #10417