I came across this after also trying to figure out why my /evolution was showing 0 for pollution and to see how much my pollution is actually contributing so I can pick the right settings.
I think you can approximate the pollution contribution, assuming the "natives increase pollution" isn't in use. You know the final evolution factor and can query the time and kill factors, so if I'm not mistaken you should be able to calculate the missing component.
I think the formula is:
ef_p = 1 - (1 - ef)/((1 - ef_t)*(1 - ef_k))
Where ef = evolution factor and ef_t, ef_k, and ef_p are the time, kill, and pollution components respectively.
In my game, my evolution factor is 0.192756, ef_t = 0.088356, and ef_k = 0.092. Plugging this into my formula, I get ef_p = 0.0247999852, which seems low (because trees were absorbing pollution without being damaged). However, if I use your evo_combine formula with all three subcomponents, I end up back at the reported in-game evolution factor of 0.192756. Thus, my pollution component is really 12%.
So I think the data can be estimated. It then becomes a question on how to surface it. Can mods introduce custom console commands without disabling achievements? If not then maybe a mod setting to show a small UI overlay with the current evolution stats for the three components.