So, as @izzymonkey stated above, the firmware 2.00 update removed the X Webcam Connection Mode and replaced it with the USB tether shooting modes. This allows the camera to be detected by the X Webcam 2 software (using version 2.1). However! The output resolution is still limited to 1024x768 and the framerate looks to be limited to 10 or 15 FPS with a lot of hitching and exposure/focus stepping. So this is not a real solution, yet.
I'd say this is a step in the right direction. Hopefully in the future Fujifilm will allow the X-S10 to output full resolution with X Webcam.
On a personal note, I ended up getting a cheap USB HDMI capture device which works well, but the colors are visibly worse than with the native output. Maybe one day...
svgnbl got a reaction from YOUTA in Fuji x-S10 and Fujifilm X Webcam