Yes, it is compatible with Nikon Z-series mirrorless cameras when used with the Nikon FTZ or FTZ II mount adapter.
Yes, it features moisture-resistant construction with seals at the mount and other critical locations to protect against dust and light rain.
The G2 version offers faster autofocus, improved image stabilization (4.5 stops vs 2.5), a shorter minimum focus distance, and the FLEX ZOOM LOCK system.