The thing that caught my eye was right at the very end of your post.
Accutane. There has been a LOT of talk lately about
Accutane causing severe gastro problems that sound a lot like what you've been experiencing with that. These problems, apparently, can show up YEARS after having taken the Accutane.
I don't know that the Accutane could explain ALL of your symptoms, but it very well may explain the GI issues and I would definitely mention it to and ask your GI doc about it.