Can autism be comorbid with AvPD? If so how common is it?
A quick google search shows that yes, they can be comorbid and there’s actually some interesting stuff written on the two if you’re into reading (or researching). As for how common it is, I have no idea.
Generally, if something is included within the diagnostic criteria, such as sensory processing disorder or selective mutism, it can’t be comorbid because autism explains the symptoms. Aka, those traits already have an explanation: you’re autistic. If something isn’t autistic traits, it’s likely they can be comorbid.
A quick way to check is searching “ASD” or “Autism” the name of the thing you are wondering and “Comorbid” or “Comorbidity”.