I have diverticulitis and am currently on a low residue diet. is coconut milk ok?

Yes: If you have diverticulitis, with pain and fever stay on a low fiber diet for 4-6 weeks to allow healing. If you merely have diverticulosis, then a high fiber diet is recommended and include 80-100 ounces of non cafeinated, non alcoholic fluid per day and this can include coconut milk.

Has good electrolyte: Pure coconut water has good electrolytes, coconut milk has additional fats and carbohydrates, which gives calories, regarding diverticulitis is a disease of western world, infrequently ( rarely ) seen in the developing world where bulk high fiber less processed food is consumed.