Couple questions on HW4

For the Buck-Boost problem, when we solve for the buck or boost part, does that mean we just choose one to work out? Seems like "buck or boost" is two different cases, so I'm confused why the problem keeps saying we need to solve 2 cases instead of 3.

For parts b) and c) I am essentially just using the two examples the professor showed in lecture 11, except for part b) where the problem statement states that Q2 is initially on, meaning the inductor current of Q1 will be multiplied by D prime, and not D. When I go to solve it in part d) though this doesn't line up for the transformer since the other side of the transformer is of the form D*Vg. Can we just arbitrarily sketch our waveforms such that the duty cycle lines up with what we need?

Also, why don't we include the reverse recovery of the body diodes of Q1 and Q4 when the cycle is transitioning between Q1 to Q2 and Q4 to Q3?

Thanks