--compression on the nerves and lack of circulation to the pressure of the position.

I certainly have both, and also suffer from developing numbness in certain parts of the body if I keep them in certain specific positions too long. Sitting too much on my left thigh, for example, will slowly bring on the feeling of the limb "falling asleep", which slowly ebbs when I shift or get up. And I have an unfotunate tendency to lean on my left elbow while reading or working at the computer, which will produce those symptoms in my ulnar distrubution.

While it's kind of difficult to explain, I can distinguish between the "circulatory" effect and the "direct nerve" effet--the numbness/tingling has a slightly more prickly, less global quality when the nerves are involved, and the circulatory issues fade faster upon pressure release.

What kind of testing have you had to find the cause of your neuropathy? A number of causes--vascultic autoimmune, diabetes/glucose dysregulation--involve a mechanism in which circulation to the nerves in compromised, and they begin to be damaged due to lack of nutrients/oxygen, so circulatory insuffiency can certainly be involved.