I don't know too much about UNG, but I'd imagine that you'd get into the Corps of Cadets no problem. For the Army ROTC, you should be very competitive. I personally think you have a very good chance.
I would definitely list them. I think you should be competitive for an ROTC scholarship to one of those schools. And even if you don't get one, you can still apply for a 3-year scholarship once you get to one of those schools. All of the military branches are starting to offer more 3-years and...
I don't say that in any disrespect to Norwich. Norwich would also be a great school. It's just that in my opinion, The Citadel would be better for wanting to commission in the Marine Corps.
Between the two, I would definitely choose The Citadel. I have heard from an alumnus of The Citadel that a few years ago, the Commandant of the Marine Corps spoke at The Citadel and stated in his speech that the Army has West Point, the Navy has the Naval Academy, the Air Force has the Air Force...