The Subtle Foreshadowing You Never Noticed In Disney-Pixar's Coco

As pointed out by Reddit user Numerous-Lemon, the foreshadowing lies in one key detail: The belt buckle seen in the family portrait is not the one worn by Ernesto, thus indicating the truth. Another user, faceless_combatant, supported this detail by referencing their own parents, who are mariachis. According to them, "You know you're a 'legit' mariachi if you have your own custom belt buckle. So it definitely is significant that they're different, as they would naturally have had different custom buckles from each other." This little detail can be seen at the beginning of Coco, and essentially reveals the truth of the story, but only viewers who are familiar with this aspect of mariachi culture (and who also pay close attention) would spot this and understand its significance. 

The detail of Ernesto and Hector's different belt buckles showcases just how much research and effort went into making Coco accurate to Mexican culture, which is one of the many reasons the Academy Award-winning animated film is so critically-acclaimed and loved by fans. Coco earned rave reviews, becoming one of the highest-rated Pixar films, only behind a handful of classics like Toy Story, Finding Nemo, and Up. Many critics particularly appreciated Coco as an original and profound movie that goes deep into ideas of death and the afterlife, while still making it bright, enjoyable, and accessible to a young audience. Even now, three years after Coco's release, fans are still gathering to discuss the film and acknowledge the creators' effort and attention to detail.