Yes it does. I am not sure about JDM versions, But the US Prius 3rd Gen has it. You just need to push the 'trip' button to display it.
Regarding your 2nd query;
I've recommended that a simple solution to the DTE is to multiply the displayed Cons. value by 10. In looking at my records, when my displayed value x 10 was nearly equal to my mileage for that tank, I've found that I put in about 10.5 gallons (+/- 0.1 gallons). This assumes that you are not purposely overfilling (i.e. shoving every drop of gas you can get into the car). Filling to the first click and maybe doing another click in case of a premature shut off. (for my car, this would be about 0.2 gallons).
For my 2010 Prius III - the Cons. (MPG) estimation is about 2 to 4 mpg more optimistic most of the time. on my last 800 mile plus tank I normally get the first beep warning at about the 660 miles mark and the distance to Empty(DTE) reaches zero at about the 686 miles mark. With respect to my first 800 mile tank, my MFD cons. was 73.4 mpg which computed to 71.1 mpg when the 11.252 gallons of gas was taken into account. My Prius probably had atleast half a gallon of gas left. The method I was using to determine my range at that time was based on a rule I got from Bob Wilson that said that at the time of the fuel gauge nearing empty warning beep that I would have about 2 gallons left. To be on the safe side I use (CONS.-3)2 to compute my range after the first beep which was (73-3)2= 140 miles. I then took 660+140=800 to compute my safe range:)