Great hero 6 ends with an adorable post-credits scene. As Fred goes through his family’s stuff, his father, who looks and is voiced by Stan Lee, shows up and says they have a lot to tell. It’s always fun to see Stan Lee cameos, and his presence in this film makes it clear that it’s actually a Marvel film. And Marvel films are all connected in some way.
After all, there was one Scene in Guardians of the Galaxy Vol. 2 Here Stan Lee can be seen speaking to a group of aliens known as guards. He mentions some of the cameos he has made in the MCU over the years, and makes it clear that Stan Lee always plays the same character whenever he appears in Marvel films. If this theory is correct, it means that Stan Lee’s observer informant also made a trip to San Fransokyo.
Granted, Stan Lee also appeared in films outside the MCU, such as Sam Raimi Spider Man Trilogy. Maybe Stan Lee’s character has the ability to travel through the multiverse to get to other Marvel universes. It may be possible to manipulate the multiverse in the MCU so that Big Hero 6 can properly enter the Marvel Cinematic Universe at some point.