Looking only at the issue of the crest: A woman is considered not to be able to bear a crest, as she does not fight, and therefore has no helm for the crest to sit on.  There is an exception made for peeresses (and perhaps baronetesses) who are deemed able to bear crests. On a strict interpretation, it could be argued that a woman cannot even bear arms, only transmit them (if an heiress), but that would be putting theory above practice, which is unrealistic and certainly anachronistic!