No, this is a manual focus lens. However, due to its ultra-wide 14mm focal length, most subjects beyond a few feet are naturally in focus when set to infinity.
No, the lens has a bulbous front element and a built-in hood. It requires a specialized 150mm filter holder system for ND or Polarizing filters.
Yes, it is fully compatible with Canon EOS R-series mirrorless cameras when used with an EF to RF Mount Adapter.