The different tone light and dark grey on areas of the body were solved recenly in another ask here. KOSDUMJUR solution
- Changed image node with the normal map to non color data. It fixed the different tone on the seams.
The black small rectilinear shapes imply they are over black areas of the left hand uv map. Perhaps they were not included in the unwrap? Select those faces and see where they are in the uv?