No, the a6400 does not have IBIS. For stabilized footage, it is recommended to use Sony lenses with 'OSS' (Optical SteadyShot) or a handheld gimbal.
Yes, it is highly rated for vlogging due to its 180-degree flip-up touchscreen, external microphone jack, and industry-leading Real-time Eye AF.
While improved over predecessors, it can warm up during long 4K sessions. Setting the 'Auto Pwr OFF Temp' to 'High' allows for longer continuous recording times.
It uses the Sony NP-FW50 rechargeable lithium-ion battery, providing approximately 360 to 410 shots per charge.