The belly button aversion reminds me of my son's aversion to gum chewing. If anyone even looks like they "might" be chewing gum he is grossed out. He can spot a gum chewer in a crowd of a dozen people in a few seconds. In his case I believe it's "misophonia" though which is a recognized phenomenon.

Does he have any hyperactivity? Focus issues? If so, look into ADHD? He also may have some executive functioning difficulties (the emotional dysregulation and lack of effort w/ work can tie into this).