Yup only fenris but it dose seem a good starting point for cerby. I think the savage abilities and frightful howl seem apropreate for the guardian of the gates to the underworld. Just my two cents though.
Wishbone eh. Is that something like cergy biteing a leg with each head and making a wish. A wish like "I wish these adventurers would come with kegs of Bar-b-Que sause strapped to their backs." I guess either way cerby wins!