So since all of the above characters are fictional, what does it matter what sex or color? I think it would make no difference if Murphy was played by a man... The tough cop thing works for both sexes, so does the love thing.. Comic book or novel? Wonder Woman can change to Greek Warrior.. Or better yet, Amazons still need men to make little Amazons, some are born boys, and what if his mother decided she wanted her son treated equally to the girls? My point stands that there is no need to change the color or sex of an existing character no matter the medium because there is no reason to create more. Oh and my impression of Sanya, is though he seems to be Russian, he is also black, I seem to remember him described that way, but I could be wrong there.
Respectfully, Murphy's a trope inversion- Jim loves these. A Murphy that isn't a petite, short, doll-like woman doesn't have the same struggles. She's an interior cigar-chomping hard-ass tough-as-nails wise guy, but she looks like a cheerleader- she was Jim doing a Buffy. She's actually a miniature Viking, and her coloring furthers the joke. (Recall, Butcher's Vikings- his Einherjar- are men who gleefully go after Jotnar. Relatively speaking, compared to Murphy, you're no Jotnar.)
Just like Harry's a clever, insightful, relatively wise (for his years) man who works with his mind- and is a hulking representative of humanity. It's a joke. When they confront you, Murphy's going to loom and Harry's going to go nice cop. Harry's the one who's going to try to entrap you in lying and Murphy's the one who's going to rough you up.
To do it really well, and capture an important aspect of the books, you'll need a director/showrunner who pushes close-ups for most scenes, so you can occasionally pan out to just how tall/looming Harry is. Harry forgets the effect this has on people sometimes- particularly other tall people who aren't as tall. It can elicit instant hostility from those who are used to looming themselves. I've always thought a well-done scene with Morgan would have such a cutaway, where Harry doesn't realize he's not "in Morgan's face" but "looming down into Morgan's face", which is inherently a bit more threatening.