> Godel's incompleteness theorem or the halting problem are applicable to everything including the human brain.
Maybe. That's if you assume that the universe is a conventional computer. Far from settled and the alternative isn't necessarily just "God does it" - it might be that the universe is a "computer-plus", with some processes that produce results not computable by Turing means. It would be strange, but so is quantum mechanics, so...
As of yet we have no such evidence of physical systems that are more powerful than Turing machines. We will consider if ever such evidence arises.
Yep, a possibility that has found support with Roger Penrose, who wrote two books about it.
This line of thinking doesn’t really go anywhere. You can say “but what if <something outside of an axiomatic system>? Then <axiomatic system> doesn’t apply!”
Well great. Then where are you? You are precisely nowhere. You haven’t disproved the results in the system and you haven’t proved anything else.