For dressing, combine salad dressing, mayonnaise, half-and-half, seasoning, salt and pepper in a small bowl; blend well. Cover; refrigerate overnight to blend flavors.
Combine chicken, shells, celery, grapes, almonds, water chestnuts and onion in large bowl. Pour dressing mixture over salad; toss gently to coat. Serve on lettuce. Garnish with reserved almonds, parsley and star fruit. Serve with cantaloupe slices.