Welcome and ditto TeDo. I was thinking along the same lines. And although you didn't go into K too much because you've got a "handle" on her issues, she may be in the same place. It's just a hunch, but ADD, Anxiety Disorder & sensory processing disorder (SPD) seem to be a very common symptom set for ASDs.
The "getting into stuff" brought back *fond* memories. DD1 LOVED powdery stuff. Corn starch, flour, her sister's formula (that made me nuts because it was so expensive!) I had always thought it impossible to make those toilet paper mazes through a house like they show on TV. Enter DD1. It was pretty cool! Of course the memory is nice than dealing with it in the moment.