This (pre) visualization of which you speak, in photography, refers to exposure of the scene and its relationship to the film processing as it serves the print.
It is a matter of seeing the range of tones in a shot as they will come out in the print and exposing for that. The second major consideration is the contrast within the scene and how you are going to process the film to manage that. If it is a high-contrast scene the developer is used for less time, if low-contrast then the developer is used longer. Exposure must render the shadows as development has little effect on the thinnest part of the neg. The brighter tones (the dark ares in the neg) are the most chemically reactive. By this method, their density can be reduced or increased respectively. So you flatten a high-contrast shot and bump-up for a low-contrast shot to work within the technical limits of the paper to render what you saw.
My own limited shooting (teacher, administration, you know...) outside of studio work is a matter of discovery, most frequently at a subliminal level. I'll be walking down the street and some tableau will reveal itself. I don't think about concept to identify it, to talk about it; this is a visual communication, after all. Very often I have no understanding of what I'm about to shoot, though I do consider framing. After that I just make sure I get the right exposure. Tonally, everything else will fall into place if the dynamic range of the scene is within the film's range,
irregardless (hee-hee) of any concept or accident.
"Happy accidents" are gifts. You might find a surprise detail, object, action, or grand concept, but that has nothing to do with the Zone System and visualization, pre or otherwise. Happy accidents are not accidental as far as exposure and processing goes. If the neg is properly exposed, whatever "thing" happens to emerge, you will be able to render it in the print.
For my part, there are no "happy accidents" in my exposure, digital, or chemical processing. As a photographer I have control of that. I just have visual ideas that have no name. The print allows me to experience those ideas and reveal their meaning.
BTW, "pre-visualization" is a real word defined by the Oxford Dictionary:
NOUN: The visualization (now especially through the use of computers) of how something will look when created or finished.
Origin: 1950s; earliest use found in The New York Times. From pre- + visualization.
However, Previsualization is referred to as a subset of Visualization, the second subset being Postvisualization.