It certainly doesn't surprise me that kids could be misdiagnosed with autism.
Type 3 sounds like my son when he was younger except there was no resistance to change. He always liked change and he seemed precocious in a lot of areas because he was so interested in everything.
He was recognizing words at two and read his first easy reader book that he hadn't seen before at 2 1/2 and was able to spell words and identify words that were spelled out for him. He hadn't been taught to read except I always put my finger underneath the words as I read to him. He always seemed to be able to comprehend whatever he was reading without a problem. If he didn't understand something he read he would certainly ask about it. He could memorize scripts and song lyrics so quickly that a teenager in the class told me that he must be autistic or something to be able to do that. He also had a lot of excess energy when he was excited about something and would kind of flap his arms like he was shaking out the excess energy and in fact that is how he described it. It was because of the stimming and talking like an adult that my sister thought he might have Aspergers even though doctors said he didn't. He stopped doing that in public when he got older and started pointing out every time I would do any kind of stimming behavior like tapping on the steering wheel when I drive in traffic or tapping a foot when nervous about something. As far as I know, I am not autistic, but I wonder if I would have been diagnosed with autism in elementary school. l did not talk to anyone outside of my family when I was in elementary school, hid in my long hair, didn't like to make eye contact, and read a lot. I outgrew a lot of my differences without any kind of therapy.
My son is now 15 and even though I don't limit video games, he reads more than he plays games and he reads about a lot of different things. His interests are definitely not limited. He wants to talk to me about what he has been reading and get my opinion and is more than happy to tell me all about it and help me form an opinion if I haven't read or thought about whatever he is talking about especially in the middle of the night when he can't sleep because of pain issues.
