Headcannons never die. There is a way around so many of those so called "headcannon destroyers" For instance:



Derpy in the credits is called Muffins, yet she is never addressed as such (or addressed by any name at all). Muffins could be a nickname (or Derpy could be the nickname) or even a last name.



Then there's always the alternate reality theory:



Every decision that is made results in a different reality all of them coinciding side by side unaware of the other's existence. Making anything possible.