We flew zipair between narita and san jose in late February. IIRC it was ~¥320,000 each, round trip--for their version of biz class/full flat, and that included our selected additions--meals, and amenity packs (blanket, neck pillow, eye shades, etc).
Not sure of seat width, but when exploring seating, I seem to remember that their economy class seat pitch was 31", which is pretty normal--I think the same as actual JAL economy class.