Hello
it sounds a bit unclear to me what exactly you need to do.
Normally you don't pitch shift formants; they happen to be the peculiar physical aspects a phonetic media overimposes on the sound it generates. When you pitch shift such sound, the formant_accurate pitch shifter should calculate the correct formant at different pitches so that the sound remains "loyal" to its character over the shift range, avoiding chipmunks artifacts.
Could you explain what exactly is t he task you are looking into?
thanks
I
