Mission 5: When you enter the Pizza Parlor you'll see that he is cleaning a mess of Hot Sauce and Chocolate Sauce on the ground, then you ask him if you can have a bottle of both. If prompted, he will also ask you to deliver the pizza on the countertop.
Mission 6: You ask for a vegetarian pizza, so Herbert will fall for your trap.
Mission 7: He confirms the Pizzatron 3000's timer is out of order since the Clock Tower was broken by Herbert. He also says that since the timer is not working he can't make pizzas and may have to switch to salads. He also lends you the music sheet near the piano.
Mission 8: You order a Double-Meat pizza with extra gray fish for a green penguin outside.