The 18p- is definitely an avenue to look into. His teeth came in very late, which I didn't connect to any of this until I read some of the characteristics of 18p-. He doesn't have the small stature, by any means. He is very tall and well built. Physically, he's very well proportioned.
As for the ASL, I wish I had access to formal classes. If anyone knows of any in the Shreveport/Bossier City, LA area, please let me know. For now, I am teaching myself and him with a hodgepodge of Signing Time DVD's and lifeprint.com.
He has a speech eval on Feb 1st (finally!!), so we'll see what that brings.