(4) Some children learn to read before they are 2.5 years old. From what I know all of these early readers turn out to be autistic.

I'm a living counterexample to this, as I learned to read at basically the same time that I picked up spoken language. I might have slight tendencies toward behavior consistent with autism, but I'm well within the range of "healthy" human variation, at least where the autistic spectrum is concerned. (My mental illnesses tend to run in other directions.)