CD is stereo and so only uses the left & right speakers in a HC system, however there are various modes available that you can select to expand the sound into more speakers if you wish, as to whether it is better is down to personal preference, but usually just left/right is fine.
Digital remaster just means they have taken the original recordings and remixed it on modern equipment to theoretically give it a better quality sound, (Although some studios use it for other purposes which makes the sound worse) however it is still stereo.
Bill