" I'd have to understand what the basis is for asserting the firing of neurons obey the laws of physics. How do you account for the "Will"? "
Hmmm. You kinda jumped from one end of the universe to the opposite end there. We know that any thought processes involve the "firing of neurons" because we can actually measure which ones fire and which ones are inhibited and we use scientific tools based on electronics and other laws of physics to make those measurements. We also know that this is the way thought is conducted because when the electrical activity responsible for consciousness stops working, we declare a person brain-dead and pull the plug.
Really -- I don't see how we can contradict that. Now, the "will", Feynman or Hawkins is another matter. The knowledge of how those firing of neurons create thought and intellect, is presently beyond our understanding. But that there's a fundamental mechanism by which that happens is hardly in doubt.
In an earlier comment I made reference to "60 Minutes" piece showing how researchers are now able to tell if you're thinking of a particular object or if you're lying about something. They can't tell what you're lying about, but they can tell the difference from when you're telling the truth. Of course, this presently requires a sophisticated MRI and a person's cooperation. But the point is that we already have a rudimentary way to ascertain what goes on in someone else's mind. It's crude, but the implications are enormous.
I'm not saying that today or any time soon we will be able to read someone's mind. I am saying that given a sufficiently large intelligence, it may be possible to accomplish what we're trying to do today: finding what's on someone's mind. I suppose I could seem less deterministic or a reductionist by stating that given the possibilities, a large intelligence may not at every chance come up with THE answer. The calculations may lead to multiple answers that are likely to occur. But it would narrow the possibilities. In that respect (not being reductionist but as a parallel example), it would be like a game of chess that is played before the first piece is actually moved. The possibilities are already there and can be projected forward by several moves, knowing that the other player has a finite number of moves at the outset.
I don't disagree with your original premise about what god cannot know but not for the self-referent reason you mentioned. The way god is explained to us, s/he is boundless, omnipotent and a limitless sage. But that also means that s/he cannot escape his/her own make up (whatever that is) and would be automatically prohibited from creating an equal. The paradox that questions his/her existence is in the contradiction of his omnipotence and what s/he's unable to do.