-Ok, so he has sensory issues- mostly hypersensitive to textures, foods. At school he is seeking out deep pressure.
-He uses repetiitive phrases and makes noises. I think this is learned from difficult child, but it is really evident at school. He will often stop if reminded/rewarded to stop. He is very verbal though. Only a very borderline expressive delay that he got services for at age two and resolved.
-He CAN BE very resistant to doing fine motor work (writing, drawing, cutting), but is ok with it at other times.
-He is anxious in large groups if he is asked to perform.
-He is anxious entering large groups if he is alone/coming in late.
-He can be very cute/charming.
-Great eye contact.
-Very affectionate (almost too affectionate with teachers).
-Is definitely capable of engaging in pretend play, especially led by neurotypical bro, but left on his own he usually seeks out computer or just kind of wanders around. He collects things, but then doesn't do anything with them (they sit on a table or in his room).
To me this just sounds a little deviant from typical, but not screaming autism spectrum. Maybe I'm in denial. Maybe my older son is sooooo affected, that this seems very close to 'normal'.
A few observations-
First, in listening to parents with more than one child on the spectrum through the years, they almost always say the second one is quite different than the first--more social, more verbal, different obsessions, more affectionate, etc.
Second, there are a group of kids I call "spectrumish", in that they show a lot of Autism Spectrum Disorders (ASD) traits, but not enough of them or not strongly enough to land an Autism Spectrum Disorders (ASD) diagnosis. Often these kiddo will be atypical in that they break one or more of the "rules"--they develop speech fairly typically or have mild delays or have advanced speech (such as with Asperger's), OR they may engage more, OR they show a lot of other traits but not have transition problems. Often they compensate well in the home and other familiar settings, but school really throws them since they're being challenged on so many fronts and have no parent around to automatically make adaptations for them. Frequently they benefit from the services used in the Autism camp and it's helpful when parents can get a doctor to recognize the borderline or atypical Autism Spectrum Disorders (ASD) status, as it can be tough getting services for this group unless they tank in one area (like anxiety).
Third, when a second child comes along with some recognizable symptoms, parents are usually quick to recognize and provide accomodations and guidance. An insightful parent can provide a lot of "life is therapy" that helps a younger child out early on, and may make a difference diagnostically.
Fourth, some of the things you have listed sound like speech/social/pragmatic issues--too affectionate with teachers, anxious entering groups, repetitive phrases--and with an IEP could be addressed through speech therapy. If his repetitive noises increase when he's anxious I wouldn't bet on those being learned either.
In my district, a child with the above list would be in a regular classroom with individual and group speech, Occupational Therapist (OT), accommodations in place to address problem spots and possibly an aide to help with the anxiety. It would be very rare for such kids to be in a self-contained classroom here, especially those who could be served in a regular classroom with support because it would be a violation of LRE. Even a part time aide to meet him at the school door and get him settled into the classroom for the day and give classroom breaks and/or Occupational Therapist (OT) breaks could go a long way. If it were my kiddo and I felt he had a chance to succeed there at the school, I'd probably be fighting it if they hadn't tried using an aide in the regular setting plus accomodations to address anxiety along with speech and Occupational Therapist (OT).
Hope this helps.
SRL