You are in a unique situation to have so many skills. I knew several deaf people when I lived near a state school for the deaf for a couple of years was young. I could sign a little bit, just enough to impart a thought or two but not enough to carry on a real conversation.

I only need to "see" a person speak when I am in a sensory taxing environment. Interestingly, I prefer to conduct business on the phone (as long as the speaker does not mumble) because I am not destracted by facial expressions and other visual confusion. Also, I can pace while I talk on the phone which helps me concentrate. And I feel more free to scribble notes which helps me keep track of otherwise unmanageable quantities of information.

I find the PTSD connection interesting as well. I regularly wonder if my SPD is connected with stressful envirnments in utero and very early childhood. Throughout my life I have experienced much worse symptoms when I am in stressful times and envirnments.