No, this lens does not feature official weather or dust sealing. It is recommended to use a rain cover in adverse conditions.
No, it does not have built-in Optical SteadyShot. It relies on the In-Body Image Stabilization (IBIS) found in most Sony Alpha camera bodies.
The DC motor is relatively fast but can produce a slight audible noise. For professional video, using an external microphone is advised to avoid picking up motor sounds.
The lens uses a 49mm front filter thread, which is a common and affordable size for ND or UV filters.