3. I remember reading that the DOF scale in the camera isn't accurate because Fuji chose to use a smaller value for COC than necessary. Is the focus distance accurate?
A circle of confusion is a group of optical engineers sitting around a table to find a definition for DOF. The COC is very much a non-absolute value and can vary widely from manufacturer to manufacturer. Many of the DOF charts on the Interwebs are said to date back to days when film was incredibly grainy and did not have anti-reflective coating on the back. To the best of my knowledge focus distance is accurate.
The COC (and thus DoF) depends on print size and viewing distance. Therefore it is the end user who must provide the appropriate number. The camera maker puts a value in based on some criteria that are probably only known to the marketing guys. I wish the X-E1 would allow me to set the COC myself, but it isn't too difficult to calculate numbers for appropriate scenarios.
However, it is much better in the real-world to do something that was impossible when those charts were first being developed. Do test shots and use the playback to determine if your needs are being met. Forget the charts, forget the scales. Use your eyes. I had a chance to photograph hockey a couple of weeks back. With the 60mm lens, I focused upon the goal and found that by f/4.0 the opposite boards were sharp, and sharpness extended into the foreground beyond the image area where significant action would take place. I shot with confidence and was rewarded by 100% sharp images.
The "eyes-approach" won't tell you if the DoF is appropriate when images are printed. Of course, one can develop a feeling for it over time, but as long as the system is halfway reliable, the numbers will tell you precisely what is going on. Unfortunately, I have my doubts that the X-E1 software (or perhaps it is the hardware) is reliable when it comes to DoF, at least when combined with my 18-55mm lens. I don't know how big of a deal it is, yet.