I'm probably way off here as I don't do any portrait photography, but when taking the portrait isn't it the distance between camera and subject that dictates the perspective rendering, and then the choice of lens is essentially a framing/cropping choice? Ignoring optical aberrations, for a fixed film to subject distance, changing focal lengths does not change perspective, only cropping. If film had infinite resolution and no grain, all you'd need is one short focal length rectilinear lens and you could just crop under the enlarger.