Century Precision Optics 0.8x Wide Angle Converter for Sony PXW-FS7 with FE PZ 28-135mm Zoom (95mm)

We are not aware of the exact light loss you may face with this adapter. However it should be minimal as this is made with high quality optics.

Sorry, that diameter is unlisted by the manufacturer. It is just as well for I can tell you as a former motion picture camera assistant (whose job was to make sure the front element of the camera's lens was "clean") that extreme wide angle lenses will see any sun shade that is actually blocking the light from hitting the lens. What has to be done is the errant light must be flagged (blocked) at the source. With medium to tele lenses you can use a sunshade on the lens. So to answer your question, there are no compatible sunshades.