You're right when you say that I am looking for the Fantastical and Mythical.
As for the second part, it sort of depends how you interpret the legends. I personally don't like the Man-Wolf idea because it just... doesn't sit well with me, really.
As for the Half-Shift, I can think of one solution: A Lycan. A Werewolf is someone who is forced to change at the Full Moon, so that is singular only. A Lycan, however, can shift at any time they want, and even do it partially if they want (can make one hand into a clawed murder weapon that can tear out someone's throat).
If you, Sara, takes a Lycan, you can get a Shift that looks like a normal wolf (albeit a bit larger and more feral looking), and also have access to a half-shift, although you'd get more wolf characteristics than you mentioned before (elfine ears, more pronounced muscles, clawed hands, taller, wolf-like eyes. Possibly even a Wolf's hindlegs, if you want to go that far. The legs are just something I think is cool, but not something you have to take).
You'll have to make a few changes, but you'll still be the same character over-all. What do you think?