Yes, the X-T3 supports 4K/60p video recording at 10-bit 4:2:0 internally and 10-bit 4:2:2 via HDMI output.
Yes, the X-T3 features a weather-resistant structure that is dust and moisture resistant, operating in temperatures as low as -10°C.
The NP-W126S battery provides approximately 390 shots per charge. For long video shoots, using the optional VG-XT3 battery grip is recommended.
No, the X-T3 does not have IBIS. For stabilization, it is recommended to use OIS-enabled Fujifilm lenses or a gimbal.