Boxing & unboxing is the process of converting a primitive value into an object oriented wrapper class (boxing), or converting a value from an object oriented wrapper class back to the primitive value (unboxing).
The Old Dalaran will stay in Northrend, so yes, mages are going to have 2 portals to dalaran (one to Northrend and one to the Broken Isles)
Rhonin is dead now in lore, he's still in the current Dalaran because that's still in the wotlk timeline, where he's still alive, now he's dead, so he won't even be there, Khadgar will be in charge of Dalaran. 1588 posts.