I finally finished this yesterday after a 3 hour slog through the last strike. I spent most of that time picking off the yellow shielded wizards with flash bangs and super smashes. When the named wizard finally showed up I fed him 5 solar rockets and celebrated in my living room like I had just one the lottery. One piece of advice; when the shrieker spawns just hang back in the precious room until it disappears. A group of mobs spawn every time the shrieker does but then disappear shortly after the shrieker. Don't waste ammo on them. Just kill the mobs you see when the shrieker is not out.