About playfields we close during server merge: They are not deleted and we can re-introduce them later when we have found a new purpose for them.
About daily missions for serenity islands: the door is still there and the missions are actually made in a cloned playfield of the cities. (translates to don't worry they will still work.)
About Tax building: It will be sold in the new vending machines.
About building tradeskills: They still exist for buildings that have not been removed.
About Towers: Tower fields will not be transferred so prepare for battle.