I WAS WRONG!
As it turns out, Yonka is ALL NATURAL. Oh joy! Though this does not change one bit my satisfaction with the Aveda line, it does mean that I can carry on my on again off again affair with Yonka's Pamplemousse for many more years to come. My life is complete.
Sorry for this major research mishap. I just had to set you all straight as soon as I found out.