First I saw how many firestorms each flier would kill if they focused all their fire on the firestorms (pretend everything is visible and in range). All barages with range is assumed to cover only 1 model and barages with no range is disregarded (harridan has bombs that are disregarded). Ork bomber would also kill 1 of its own due to misfire but that has been taken into account. Also remember fliers get additional -1 TSM for "shoot the thin part":