it seems like those two were really minor characters. they both appeared at the beginning of the sesame Street Special, and in the opening sequence of Sesame Street: 20 and still counting, but they didn't get any lines or cast credits. However, Willy spoke at the beginning of Sesame street presents follow that Bird and got credited, and Mr. macintosh made a brief cameo, had a line, and was credited in Sesame Street Home Video visits the Hospital. In that video, big bird called him "mr. mac". did big bird normally call him that, or could his line have been cut of? did they normally get cast credits on the show?
by the way, both characters were played by people who worked behind the scenes on Sesame Street. willy was played by puppet builder kermit love, and Mr. macintosh was played by floor director chet O'brien.