Wait, you forgot one interesting question. This paper claims that a Turing machine can not be a general AI, but it says nothing about other models of computation. The notion that (quantum) Turing machines are the most general/powerful model of computation is only a conjecture, although a very plausible one (usually called the (quantum) extended Church Turing thesis).
But even with that in mind, this paper does not seem convincing, including for the reasons you already mentioned. Hopefully it will spark a conversation though.
But even with that in mind, this paper does not seem convincing, including for the reasons you already mentioned. Hopefully it will spark a conversation though.