The Incredibles Poster
This easter egg can be seen in all versions of the movie.
When Miguel and Hector are on their way to the talent show, we are shown a series of scenes of the nightlife in the Land of the Dead. During the scene where a mascot sets off a Catherine Wheel firework, if you quickly look to the right of the screen on the wall there is a poster of The Incredibles with the Incredible family as skeletons.
This easter also doubles as a “prediction egg” for Pixar’s next movie, The Incredibles 2 set to release 7 months after Coco. Pixar is notorious for putting references for their next movie into a preceding film like when they put Nemo (2003) in Monsters, Inc. (2001) or Lotso from Toy Story 3 (2010) in UP (2009) .