Photographs don't have to be real. You can dummy them up if you want.

If your vision/goal is to show similar photos with different colors, you don't need to use real chems. You could, simply, use colored water. That way you could have the exact colors you think will produce the best series of images.

If your vision/goal is to actually document the colors of different chemistry as it is being poured out, that would be a horse of a different color.
The thing is I don't think you'll get the exact colors you had in mind.

Kodak Indicator Stop Bath is naturally a bright yellow color. When it has been exhausted (by being exposed to too much developer) it turns purple.

Different films have antihalation dyes that wash off in the first rinse. You'll often see deep blues, greens and/or almost black, depending on the film. However, if you put developer in first, without pre-rinsing, you usually don't see any color because the developer destroys the dye.

Some fixers start turning a light gold color when they are becoming exhausted or when they get old.

Some developers turn brown or straw colored when they are used up or get old.

My Arista E-6 color kit has chems that range in color between light blue, purple or a tinge of red. The blix solution is a dark color.

Other than that, I don't know anything else, that would have interesting colors. From what I have read of your post, I don't know if those colors will fit with your vision.

That's why I suggested dummying them up.