Sure, that alternate form is fine. The only change I'd make is to drop the "(its natural form)" bit. The original calls them "humans" that "transform themselves into hyenalike forms." And lycanthropes don't have one natural form or the other.
Yes, I'm aware of that but we've made it a Magical Beast hyenawere, so it's a therianthrope with an animal form as its true form.
Still, I don't mind dropping the natural form.