if the fading is due to light exposure, then I think that’s something that is hard to predict, unless you know the specific dyes that were used, how the fabric and dyes were prepared, type of light exposure etc. You can do light exposure tests for all your fabrics, but those take time, requiring the samples to be exposed to direct sun for weeks to months to get clear results. There are so many different ways to make individual colors and to get that color on fabrics that it would be difficult to generalize based on the hue alone, without actually testing.
Rob