Is Howard Morris the elusive third in this case?
From Slate.com: "John Fiedler, the voice of Piglet in Disney's Winnie the Pooh movies, died on Saturday. Fellow cast member Paul Winchell, who played Tigger, died the day before, and Howard Morris, the voice of Gopher in some early Pooh films, passed away last month. When a voice actor dies, what happens to his cartoon characters?"
http://www.slate.com/id/2121686/