p.1 #2 · Any limitations with your alt lenses when doing video?
The first thing that pops to mine: Changing aperture can be heard if using an on-camera microphone. I've read that some modify lenses destined for video use to remove the click stops for just this reason.
p.1 #3 · Any limitations with your alt lenses when doing video?
Manual focusing lenses usually have much smoother focusing rings than the AF ones. That silky feeling of focusing and zoom ring of Angeniux 45-90/2.8... Both can be easily rotated with one finger without shaking the camera. Unforgettable
Aperture can be changed during shooting but you'd want to remove that little metal ball that makes it click. Metering is done by the camera, so it is not affected by the lens choice, but with some lenses, interestingly, you may need to adjust exposure compensation a bit as you close down or open the lens. Not sure why. But it's a rare exception anyway.