In some ancient civilizations the Wolf was a symbol of the underworld. In Egypt, the guardian of the dead was Anubis who was a wolf-headed god. The jackal portrayed as black was the symbol of both death and regeneration.
William is also the one who hid inside the suits and kidnapped and killed children, leading to the assumption that William Afton is The Purple Guy of FNaF 2 and 3 (he is killed at the end of the book when Charlie sets off the spring locks in his suit).
Papa Smurf is the leader, father, chief and king of the Smurfs, one of the protagonists of the franchise, and can be easily distinguished by his red clothes and bushy white beard. Smurfs turn to Papa Smurf when things go awry. Papa Smurf is skilled in making magical spells and potions.