Shrimp and Sausage Jambalaya

Name: Shrimp and Sausage Jambalaya
Ingredients: 1 tablespoon olive oil; 1 pound sausage, such as kielbasa or andouille, sliced; 1 pound smoked ham, cubed; 1 tablespoon butter; 1 medium onion, diced; 1 cup diced celery; 1 green bell pepper, cored and diced; 1 red bell pepper, cored and diced; 1 cup seeded and diced tomato; 3 garlic cloves, minced; 1 jalapeno pepper, seeded and minced OR 1/2 teaspoon cayenne; 2 teaspoons diced fresh oregano; 1 teaspoon diced fresh thyme; 2 tablespoons tomato paste; 6 cups chicken stock, preferably homemade; 3 cups long-grain rice, rinsed; 3 bay leaves; 2 teaspoons kosher salt; 1 teaspoon freshly ground black pepper; 6 to 8 dashes hot sauce, optional (recommended: Tabasco); 1/2 cup chopped scallions, divided; 3/4 cup chopped fresh parsley, divided; 1/4 cup freshly squeezed lemon juice; 1 pound medium shrimp, deveined (20 to 24 count)