These arguments are basically sound but they don't prove that Atheism is true. They still leave open the possibility of Naturalistic Theism, which I describe in this paper. https://www.academia.edu/35251245/Naturalistic_Theism

I would also suggest that you remember that arguments from necessity (including my own in the paper linked above) should be viewed with some scepticism. Such arguments are true only on condition that certain background assumptions, often unstated, are also true. As Dennett says, It is very difficult, perhaps impossible, to tell the difference between a failure of imagination and an insight into necessity.