Thanks, Sebastian! One of the strongest arguments against the Fragility of Life Hypothesis is that evolution through natural selection may be meta-stable. If life is diverse enough, it becomes difficult for Kamikaze mutants to kill all forms of life. As long as some life persists, competitive Lotka-Volterra equations suggest that populations in the ecosystem will stabilize after the catastrophy.
However, the most reliable way to assess the true stability of life, free from survivorship bias, is likely through detailed evolutionary simulations and continued exploration for life within our solar system.
Good point. Will add a bit of a better bridge for part 3 (that I hope to realease in a week).