Does incoherence/meaningless lead to strong atheism, or non-cognitivism?
I hold that incoherent/meaningless only leads to non-cognitivism, which in turn leads to weak-atheism.
Once you defined something as being incoherent, unknowable, incomprehensible, etc, you can no longer speak of it, at all, and this includes saying it does or does not exist.
Our inability to evaluate whether god exists does NOT lead to the conclusion "god does not exist". It simply means we cannot evaluate whether god exists.
It is therefore a non-sequitur to say "god is meaningless/incoherent, therefore god cannot exist".
I do think this is a pragmatic argument for saying god does not exist, but it is not a metaphysical one. This is an important distinction.
I would agree that only meaningful propositions can be shown to be true. But I also hold that only meaningful propositions can be shown to be false. To say something is false/untrue is to hold that statement IS meaningful, but factually wrong. Thus, meaningless propositions are simply meaningless, they are neither true or untrue.
"It is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring" -- Carl Sagan