MK13, I think some of this may not become clear for a few years, possibly until he's in school, and that was the upside of the older approach where they would not give a diagnosis to higher functioning kids until 6-7 (well that was the case here in Australia). The disadvantage of delayed diagnosis is that early intervention is useful and needs a diagnosis to get funded access...
I think the fact that neither of your kids are in school yet means there are things you just don't know about what developmental challenges, that you don't see as a real problem now, might look like later (if they are not addressed now). I do not mean that to sound at all condescending, which I am sure it does, but I couldn't think of a better way to say it. My intention is not to condescend, I am purely reflecting on the things I didn't know that I didn't know with my eldest child.
And I guess I should make it clear that I come from a perspective of: my child with Aspergers did not get diagnosed until 10 years old, partly because she is mild / very high functioning (and a girl), partly because of what I didn't know back then, partly because of all the other things I thought it might be along the way and partly because of all the things that I failed to take as red flags when she was small. When she LOVED to swim, was able to learn swimming with me 1:1 (by that I mean that I stood in the water while she self taught, but would not tolerate my instruction) but melted down over swimming lessons - I blamed the lesson structure/teacher and pulled her out and kept doing "what works for us". When her first daycare/preschool experience failed - I pulled her out after 2 weeks, blaming the preschool (and yes there WERE issues, I wasn't completely wrong, I just failed to see my child's part in the problem until years later). I could write an essay on the stuff that I normalized along the way, and some of that normalization came from personal mindset, some came from the style of parenting books I chose to read (books like "Raising Your Spirited Child" for example did give useful strategies and added to my parenting tool kit, but they also reduced my inclination to see a problem with my "HIGHLY sensitive" child)... Along the way to Aspergers we visited SPD, CAPD, Dyslexia, EF disorder, Visual Spatial learner, developmental co-ordination issues etc... Until finally I started seeing that most of these disorders are absolutely valid conditions but I no longer believe that most of them are free standing conditions (most of the time), perhaps if you have just one, but especially when you have a cluster of them that they are more likely SYMPTOMS of a more global neurological delay or disorder, a disorder that makes sense of it all clustering in one child. When you have a child with sensory issues, attention issues, processing issues, social issues and and and... then you need to start asking "What pulls all of this together?".
And it sounds like your child really does have major social issues (which you perhaps aren't perceiving that way yet because things are fine at home when it's just him doing his thing and having a nice time and learning lots of stuff that interests him). Again I am not a professional or an expert, but every time you try to explain why you think he is not on the spectrum I read and think "What you just described sounds exactly like a gifted child on the spectrum to me".
I agree that the speech therapist he's had doesn't sound that useful, that the assessment sounds poorly done (1/2 an hr shocks me, and I too have been pissed at things I have seen mis-interpretted in my kids reports). But I think the answer to that is to get a proper full assessment done by an expert you respect and then see where you go from there. And also coming back to the start of my post - it may be that he is borderline enough that you won't know for a few years, but the intervention you do now will hopefully make a big difference later - assuming of course that it's decent intervention!
