Magebane damages the enchanted creature whenever they cast a spell, including from a wand.
Anyone can use a normal dark spell, but not anyone can use a dark mage only spell. In order to use a dark mage only spell, you must have training in the dark school. The only mage currently trained in the dark school is the Warlock, but the Necromancer will presumably be trained in the dark school as well. This is different than Warlock only in that other dark mages can use dark mage only cards but only the Warlock can use Warlock only cards. The Warlord is not trained in dark magic, so I'm assuming you meant the Warlock.
The Daze condition is removed after activation. Your quick cast will not remove daze, but it doesn't matter what you do with your activation. It would be removed even if you didn't take any actions, just flipped the marker.