Hypotonia is a nonspecific symptom that is found in a lot of people who have a wide variety of neurological problems.
Re: birth trauma. Obviously you are a compassionate mom who wanted the best for child. Is it really fair to expect more than that of yourself? You don't have the ability to time travel and fix the past, but you do have the ability to do something about the here and now. Is therapy an option you'd consider? It might be good to have a place to process some of this stuff and get in the moment. I will toss out two bits of information you may want to process. First, there may have already been neurological differences that lead the complicated birth in the first place. It is easy to conclude that the difficult birth lead to the neuro problems, but it may have been the other way around. Second, there are many people who have kids with complex neuro problems who had fairly simple births. That's what happened to me.
As far as the stuff your son is experiencing...It is great you are getting help from the OT and the developmental specialist. It may not seem like it now, but bit by bit this stuff will make a difference. It is easy when you first get a diagnosis to notice (and worry about) a lot of stuff you didn't see before. It doesn't mean though that all of it is really worrisome.
The impression I got from your post was that the most difficult part may be anxiety. I'm wondering if he's seen anyone specifically for that problem. We are dealing with a similar set of concerns, and getting help for anxiety was really important for a couple of reasons. First, because the unchecked anxiety was the foundation of a lot of other problems. Anxiety can get in the way of attention, socializing, etc. It was really hard to make progress in OT with an anxious child. One lucky thing is that your son has a good brain and is capable of learning new things. It is possible to learn to be less anxious and to cope better with fears. Working on this now will help him for his whole life. If you have not already done so I would read the book Freeing Your Child from Anxiety and ask the pediatrician if there is a good therapist in the area who works with anxious kids. You may want to ask specifically for cognitive behavioral therapy.
This is getting long so I'll wrap up with just one more thought. How is his diet? Have you looked at all at supplements? This is anecdotal but I've seen many 2E kids (including my own) improve with some brain support type supplements. This seems to especially be the case with kids with stimming and CAPD type symptoms. Fish oil is often the most helpful supplement. Nordic Naturals sells quality mercury tested oil. It might also be worth investigating zinc and iron deficiency. Those can be linked to stimming behavior. We saw mouth stimming type behaviors disappear overnight with zinc supplementation. (and like a lot of things that suggestion came from another mom, not from a doctor!)
