Kefir is high in histamine and can also add to the symptoms that you're experiencing. It may help to move the bowels because of the probiotics, or it may be due to your body's reaction to the dairy, causing an increase in inflammation and irritation, and therefore more bowel movements.
Trace minerals in higher amounts pulls water into the intestinal tract and increases bowel movements. Herbal and conventional laxatives work by containing an irritant to the intestinal wall. The irritation causes the body to flush water into the intestinal tract to try and get rid of the irritation.
I would try the trace minerals in high amounts. As soon as you start taking the Plan supplements, that can induce changes, as well.
I haven't found dairy to work well with the Plan. Dairy allergies are hard to eliminate, especially those tied to conventional, pasteurized, dairy products.