Different kinds of beans cook at different rates, so it's best to prepare them in separate pans (working in batches if necessary). The salad can be made with just a few types instead of all five, as long as the total amount of dried beans still measures 2 1/2 cups.
Those dried beans in your pantry started out as shell beans. But during their brief season, you can buy those same beans fresh in their pods. The fresh beans have an incomparably creamy texture, don’t need to be soaked before cooking, and cook more quickly. One of the most widely available shell beans are cranberry beans, identifiable by their pink-and-cream mottled pods. Edamame and lima beans are other varieties that you may be most familiar with in their frozen forms, but are worth seeking out fresh. Also keep your eyes open for heirloom varieties of shell beans, including scarlet runner, Jacob’s Cattle, Ojo de Cabra (Goat's Eye), and Black Calypso.