1 camera, 1~2 lenses, cables, small accessories; for example, Sony A7 kit (24-70mm), Sony A6400 kit (18-135mm), Nikon Z50 kit (16-50mm f/3.5-6.3, 50-250mm f/4.5-6.3), Fujifilm X-A7 kit (15-45mm), Fujifilm X-T20 kit (XC 15-45mm), Canon EOS M200 kit (EF-M 15-45mm), Canon EOS R5 kit (RF 100-500mm); power bank, ipad mini, data cable, mobile phone, etc. Lens that can be installed: diameter ≤12cm, height ≤26cm 

The strap is 130cm / 51". 

Yes, this bag has padded shoulder straps. 

All adjustable ND filters have this problem. The larger the focal length used, the less the cross shadow will be affected. There will be obvious cross shadows and vignetting in the large light reduction gear. If you continue to rotate, the shadows will disappear naturally. This is a physical phenomenon, not a product problem. 

No, you can sling to the front and then you open it, very impressed with this bag.