The "transient response" you should plot is the step response. You can pick some values of q1 and q2 from part (e) that give you interesting plots (you should pick plots that differ significantly from one another if you can).
A plot of z only (not zdot) is fine for this part as well.
Now that we have a closed-loop controller, we want to give it reference positions to track, so a step input is r = [1,0]' and the control signal will then be u = K(r-y).