How can one reconcile the description of the Messenger of Allah's (peace be upon him) hair (its form and length) with women cutting their hair short like a "wafra"? And is this considered an imitation of men or vice versa, especially since the form and length might be similar?

Among the forms and characteristics related to dress, adornment, and other matters, some are specific to men, some are specific to women, and some are common to both. The prohibited imitation is that which is exclusive to one of them. Thus, a man does not imitate a woman in what is specific to her, and a woman does not imitate a man in what is specific to him. The characteristic mentioned in the question is common to both men and women, so there is no contradiction.