Combine first 6 ingredients in a large bowl, stirring with a whisk; set aside.
Place quinoa in a medium saucepan, and cover with water to 2 inches above quinoa. Bring to a boil; cook 3 minutes. Add edamame to quinoa in pan; return to a boil. Reduce heat, and simmer 5 minutes or until tender. Drain and rinse with cold water. Drain. Add edamame mixture, mushrooms, and bell pepper to juice mixture; toss well to coat. Cover and chill.