Autism is wildly different though, my two with it are nothing alike in fact they are EXACT opposite pretty much.
My DC1 is very shy/quiet he struggles being around others as in he can't work out what people mean/want so spends most his time alone, hype logic/fact driven (no creative side at all but great with maths, history, science anything 'provable') and his key thing that was his 'tell' is he outwardly expresses no emotion (including pain).
My DC3 however always wants to be around us and touching us, very imaginative/creative/artsy (always loves to be writing stories, making things, drawing) and very expressive but hyper sensitive to certain words and spiral/meltdown and need to shut down and 'reset'.
They literally could not be more different... neither wear ear defenders, neither have any noticeable issues with eye contact or have any interest in fidget spinners. I don't think theres any 'obvious' thing you could do to a doll to represent my two.
I think having add on accessories you can buy that represents all different 'aids' that are available would be great but they should be retro-fittable to all dolls so you can mix and match dolls and aids to make the one that suits you. Many people with disabilities have more than one condition too, its not wild to think someone might be in a wheelchair, be autistic and have hearing aids etc...