I think Izzie will come back after a short break since they didn't straight up kill her off. Heigl probably would like some time to do some movies then return after this hospital merger situation clears up. I doubt they will fire any more original doctors.

This was an interesting episode. It was like Rashomon times four. Visually it worked, but logically it didn't. I think Webb would have found the cause of death earlier, then by checking paperwork, discover that Kepner failed in checking the patient's airway. The multiple perspective storyline was done purely as a gimmick. However, I think it was enjoyable to watch.