To recap, Buzz Lightyear the toy is based on an in-universe IRL astronaut named Buzz Lightyear, and said Buzz Lightyear also had a toy line and a cartoon based after him. This is based on the in-universe, "real" Buzz Lightyear.
Nothing is non-canon so far, and the reason they're casting a THIRD actor for the character is to help clarify that this is a totally different person.
Fuck that was a mess to type up.
TL;DR: Cartoon and movie toy Buzz is based on this guy, and "Lightyear" is his story.