I honestly do not know much about KD, but I can give you a few foods to avoid that I know are high in phosphorus.
Pumpkin, peas, corn, sweet potato, mushrooms, broccoli, and spinach are a few that I would definitely avoid.
High-protein foods, such as dried beans and peas, tend to be high in phosphorus as well. Green or wax beans would be an excellent substitute for peas.
Foods that are high in both potassium and phosphorus can also be potentially dangerous. These include dairy products (especially cheese and egg yolks), nuts and peanut butter and should also be avoided.