A. Violet Hold gets teared apart from the city as it's moved due to the "heavy" magic stored within, making it a floating instace amidst the smaller islands.
B. It moves along with Dalaran into Dustwallow Marsh and remains to be accessed by both factions like the Stockades and Ragefire Chasm are through the LFD and instance entrace. ( Either as a level 30-40 or 74-77. )
C. It becomes obsolete.