"This wiki is written in an "in-universe" perspective. Assume you are an omniscient inhabitant of the DC Animated Universe living at a point in time after all events in the DCAU have already occurred, and you are writing an encyclopedia entry. Any "out-of-universe" info is written in an article's Background Information." [emphasis mine]
At that point, practically everyone is deceased. We list the on-screen deaths in List of deaths.