Because the knowledge about yourself is covered in core abilities such as Rituals, Law, Politics etc.
No, they don't. They may get one IC for one reason or another, but to force Garou to have the flaw Ward without getting points for it is not canon, and doesn't make sense to me.
Two reasons, really. 1. There's 100 Nuwisha on earth at a given time. That makes it difficult to explain why here, why now. 2. Because you need four books to handle Nuwisha, namely the old Breed Book, the 2nd ed. Players Guide to the Garou and revised Players Guide to the Changing Breeds.