Regarding the fundamental mechanisms. This is the view that I subscribe to as well.

It explains "stimming". Repetitive behavior is soothing because its predictable. And it explains things like toe walking - feet are sensitive, and the inability to predict the stimulus of things we might step on is uncomfortable. Folks with autism may have a heightened discomfort with unpredictable sensations.

There is growing evidence that atypical dendrite development in childhood and early adulthood is linked to autism, schizophrenia and epilepsy.

I see autism and schizophrenia on a spectrum of predictive processing failure. Normal folks typically cannot tickle themselves. But folks with schizophrenia can - probably because its difficult for them to predict their internal sensations.