I have owned and dove all of the above. The arctic isn't really a heavy undergarment. It is what I use in 70 degree water. The halo AR is a bit thicker than the arctic, but not nearly as thick as the halo 3d.The Halo AR might be thinner, I'm not sure. The Arctic is slightly thinner than the Halo 3D. As to the rest, I have no experience. Personally I wear some cheap (heavy duty) base layer from Amazon and the Halo 3D on 95% of my dives.
The only person I know that had owned both (maybe all 3 AR, 3D and Arctic) is @Tracy.
Merino wool also works amazing as a base, but it's pretty pricey. If I was planning to spend money on a base it would be the thickest set of Merino I could buy. It's not scratchy, very comfortable and ridiculously warm.
Temperature wise, I found the AR and the 3D to be comparable warmth wise. The AR advantage is the lack of bulk.