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).
Great question! I don't think there will be a movie about FNAF, but there will be games though! I sure hope that Scott will make a movie soon! There have been rumors though that there will be a movie made by Sony Entertainment and Universal Studios, but Scott is the creator of FNAF and his name wouldn't be in lights, so it isn't true. I also love that you are a fan of FNAF and I think you are an amazing drawer!