Here is a shot of the camera in the bag.
There is a fabric strap that can secure the camera in place. It is not in use here.
It has a Contax Zeiss 28-85mm lens on it, which is fairly small. I packed some items in front of the lens to keep the camera from sliding around. With a longer lens that wouldn't be needed.
All the basic accessories fit, plus two extra lenses, and there is still plenty of room for more stuff, even more gear mounted on the camera itself.
When I was out shooting I left the extension arm on, but had to fold it back and collapse some of the dividers. But it fit. I think going forward I will just remove it. That is a fast mod to make.
I am not certain if a matte box would fit; a narrow one might. Even then, you could remove the battery. But if the matte box is wide, the dividers right have to go. I can check when I get back to my studio after the weekend.
Sorry, no batteries yet to test the lighting system.
Even with the top handle and viewfinder installed, there is room on top when the bag is closed, so I expect a mic would fit, too, if it were mounted wisely.