Why the differences in foliage colour?

Because of the violent weather swings associated with the early monsoon season I have moved the plants. Subsequent to this move all the plants have demonstrated significant growth. Along with the growth, the colouration of these plants has become closer. My assumption is that their previous location was suboptimal and that this along with the other answers was contributory.

these are clones so the differenes are 100% about the environemnt. not all volumes of soil are the same. you have a plethora of different variables fore ach of the plants regardless of your perception of context. are the lighter ones in more light? did you recently bring these plants outdoors and were under artificial lighting before this point? that would explain a lot. The drainage properties of those pots is lacking. there's no perlite or perlite-equivalent to improve it.. roots are sopping and soil will compact more. could be all sorts of differences in teh rootzone you can't easily observe. this sort of context is also ripe for more microbial problems as the soil stays overly wet for long periods of time. plant growth doesn't magically shift gears cause you top it. it just spreads out the growth more -- may even look slower on any individual axillary bud growth but overall will be similar rate of mass added per day, because that is dictated by amount of photosynthesis per day taking place. can't grow without building blocks (nutes + co2) and energy to piece the molecules together as dictated by the DNA instructions. topping or fimming doesn't supercharge growth rate. it's for shaping the plant. it's not magic.

While they may start out with the same genetics, they are individuals. Since you have trained them differently, they will need differing levels of nutrients and therefore the plants will look and grow slightly different. Topping and fimming will cause the plants to use more energy while they recover. The lighter leaves could mean those plants have used a bit more nitrogen or other nutrients. Good luck 👍