I am trying to find out if any other model years will fit interchangeably for replacing the doors, both doors, the entire doors(not just the small parts) on a 1986 ford mustang coupe? like will the doors from a 1987 ford mustang coupe fit? or will the doors from a 1994 fit the '86?

If you happen to find a different year but the same generation of that vehicle for doors to re-use I wouldn’t say I disagree on them fitting. Just be sure they do as otherwise it’s probably gonna be a big pain!