Note on Griffiths 9.37

Ignore Griffith's answer to part (d) (his equations 9.203).  What he wants are the transmitted fields, but he has chosen the phase of the amplitude E_to to be zero, which is not possible in general, if the incident field amplitude has zero phase-- the usual assumption.  Your (correct) expressions will look a bit more complicated.
Proceed with (e) and (f) using the correct fields.