So far the English version will at the very least go up to the 4th great ninja war, and catch up with future content in the form of updates. On terms of 'characters joining you after they died story-wise', it seems a lot of 'story battles' include the participation of a guest character (an example being Kakashi during the early missions) but you can get certain characters permanently by completing missions and for others you'll just need to start collecting the necessary materials to unlock them in your roster.