You know the entire narritive is about the misconceptions you have about all these monsters. Also you're forgetting important things like no one saying its full werewolf, but full beast. Did you see Nina's beast form? Even better did you see Nina and Peter running through the woods as full wolves? Most werewolves in fiction don't have three forms, they have one. Their full instictual werewolf form is a big ol wolf. The big ugly thing is the beast (even stated going full beast, not full werewolf). They aren't supposed to be pretty, they're monsters. Thats why they keep referencing the "Great Wolf" because its probably more like what you'd see in most fiction.