Paladins in this edition have no alignment restrictions whatsoever and, in fact, could be construed as MORE likely to sell their souls as part of an oath. I could certainly see an LE Paladin doing so for the Fiend pact, an LG one doing it for the Undying Light, a True Neutral one doing it for Undeath, and a Chaotic Neutral one doing it for Great Old One. Fae could be pratically anything.
The only DMs who would do that are the ones who just really aren't familiar with 5E.