I think you're mistaken. Did you drink homemade goat milk kefir, fermented for 36-48 hours? It is very unlikely you would be allergic to it, as most of the lactose is digested that way and the casein in goat milk is very easy to digest. What you felt could very well be a healing response due to the kefir killing pathogens. Kefir IS a powerful antifungal and antibacterial. I myself reacted dangerously to kefir at first, and got no problems with it as I got healthier.
Also, I very doubt you're allergic to things like carrot and spinach, but yes some people have problems with nightshades. Carrot and spinach, especially taken as a juice, can provoke powerful cleansing reactions, due to their actions on the liver and the gut.
The juices you drank during your juice fast are not likely to bring many benefits for your leaky gut and colitis, apart from the cabbage and the pomegranate. You need to know that juice fasting is generally not a cure in itself, but is the best thing you can do while you're trying to heal from a health condition, as you provide the easiest thing to digest to your body with abundance of vitamins, minerals and enzymes. Also, for good results, one needs to choose specific juices that will help his condition.
Last thing, most probiotic pills are too weak to induce any progress, and most strains they contain are not usually able to adhere to the intestinal walls.