Do I need to turn in a block diagram of my PI controller for problem 2?

Good question, because the printout is in response to part (a), but you don't actually have to design the controller until part (c).

However, your diagram for part (a) should at least have a block in it representing the controller, so as long as there is a description of the equations in this block as stipulated in part (a), don't worry about turning in a printout of your actual PI implementation.