What were the fates of the four main characters in American Graffiti (1973)?

As noted at the end of the film, John Milner (Paul LeMat) was killed by a drunken driver in December, 1964;

Terry Fields (Charlie Martin Smith) was reported missing in action near An Loc in December, 1965;

Steve Bolander (Ronny Howard) is an insurance agent in Modesto, California;

Curt Henderson (Richard Dreyfuss) is a writer living in Canada.