I think the severely autistic person featured on youtube videos under cdfoakley and kgaccount show someone with the "autistic like" behaviors you discuss when it comes to constant humming and those incessant vocalizations.
So I have many strange behaviors but I've usually assumed it was my social anxiety until I came across something on the internet about Sensory Defensive
I'm a teen who was diagnosed with level 1 autism at age 13. Since I was very young I had sensory issues, they were very noticeable when I was in preschool,