I've made progress on switching up the terrain so that it is more 3D rather than 2D (with the same rolling hills forming lengthwise along the terrain as scene in Pt. II of this post). This was done with a simple index that looped through the eight frequency bands I had. I temporarily considered extending the number of frequency bands to a larger number, in this case either 64 (as that would be the eight bands I had, but squared) or 121 (which was the total number of vertices making up the square of the terrain mesh). I may come back to this idea, but for now it was too much.
There are still clear diagonals and patterns in the terrain that the eye can pick up, but I don't mind so much yet, as it already looks much better than the prior version looked. Eventually I will look to mix up these diagonals. My attention turned toward the applications of the buffers that the tutorial setup, and while they look good at first glance, I cannot find any segments of code that actually apply the buffers clearly, and parts of how the buffers are updated in relation to the frequency band data that has already been collected is quite fishy to me. The sudden spikes of the piece I'm using as an example are infuriating to me, and I really want to get to a spot where the user has full control over the smoothness of the motion of the terrain from the editor. So next time: buffers, buffers, buffers.
For momentary data clarification: the frequency bands are derived from a Blackman FFT window that is included in Unity's API. These frequency bands are then passed into another function that creates audio bands out of their information, which I realized had slightly better numbers, but I had been using the frequency bands up until now. The audio bands helped a bit with the smoothness that I wanted to see, but not enough.