I'm a bit suspect of using magic to obtain inhuman/supernatural/mythical traits in anything but a temporary capacity myself; if it were possible, or easy, we'd have the Dresden version of the X-men romping around.
The difficulty is that when it comes to magic, changing something has an impact. Change someone into a dog, and even if they retain their higher faculties, they are ill-equipped to utilise the various abilities their new form presents. Change someone's physiology to an unnatural degree, and you're just as likely to set off an unstable chain of mutation, give them cancer, or otherwise mess with them in a bad way. The books state that healing magic isn't all that much better than modern medicine because you have to understand exactly what it is you're changing in a person, and even a trained biologist or doctor would be hard-pressed to work out the repercussions of introducing the inhuman attributes.
Theoretically though, it might be possible in a limited capacity using something like an item of power to maintain the spell, prevent it from causing unchecked repercussions etc. Kinda like an iron lung doesn't replaces your lungs, but helps regulate your breathing. Considering the advanced biological manipulation in place, the spell would probably require constant fine-tuning to prevent it from going wrong or messing something up.
I'm sure there are other ways to temporarily gain such inhuman traits via magic, but as a long-term deal? Much more difficult, and fraught with obstacles.
