Overall, an excellent rebuttal. However, I am unconvinced of two contentions: that the Lemay leaflet shown was dropped on Hiroshima just before the bomb, and that a fourth atomic bomb was available if needed after the test bomb, the Hiroshima bomb and the Nagasaki bomb.
What I’ve earlier heard is that Hiroshima was warned a couple of weeks previously that it might be bombed — as were several surrounding cities. This without reference to the kind of bomb, as the Allies were considering conventional bombings of the area. Hiroshima wasn’t the originally intended target of its nuke — there being no GPS in 1945, the bomber had to see the target.
The fourth bomb didn’t exist yet, but its components were expected to be ready to assemble in a few weeks. Japan surrendered before it was needed.