There's no argument to be had for atheism = religion.
* a strong belief in a supernatural power or powers that control human destiny; "he lost his faith but not his morality"
* an institution to express belief in a divine power; "he was raised in the Baptist religion"; "a member of his own faith contradicted him"
It doesn't fit either of these at all. Look at the second especially: atheism is not an institution, and has no kind of organisation. It might work if you start twisting the definition of religion, but if you're allowed to do that I'm not sure why any atheists should care.
Atheist = belief has more of an argument to it. I feel it's more the abscence of belief - after all, atheist is "without a god", not "There are no gods".
God is Schrödingers cat
Not really. There's nothing to suggest He's in a superposition of existance or non-existance. It's just "something we don't know and which doesn't matter in the slightest".
Atheists who claim they withhold any belief to wait for (scientific) evidence, believe in evidence. That's a belief. Even worse, it's a religion!
It does NOT fit the definition of religion in any way, shape or form. I guess you could call it a belief, but it's one that everyone has to follow if they don't want to die almost immediately.