Some natural things are great for you. However... keep in mind that Poison Ivy is VERY natural and 100% Botanical... and it's NOT so great for you
Another natural/botanical thing is pollen. Ragweed. Mold. These things can cause horrible allergic reactions in people. I have clients coming in all the time who tried some magic "tonic" they read about on Pinterest and they end up with a rash on their face. Sometimes you want to trust the professionals, and leave the "eye of newt" alone. If you want suggestions for "clean" cosmetics I can give you some.
As for grooming with apple cider vinegar- try a "shot" of it during the rinse. It will "strip" any build-up out of the fur. Just avoid using it on/near the face and RINSE RINSE RINSE it out. It's acidic, so it will make your dog's pH fluctuate and potentially cause a skin issue.