No, the original Sony a7S records up to 1080p internally. To record 4K video, you must use an external recorder connected via the HDMI port.
The Sony a7S is rated for approximately 380 shots per charge when using the LCD screen, or about 60 minutes of continuous video recording.
While it has a lower 12.2MP resolution, it is excellent for still photography in low-light environments where minimizing noise is more important than high pixel counts.
No, the original a7S does not have IBIS. You will need to use lenses with Optical SteadyShot (OSS) or a gimbal for stabilized footage.