all-new featurettes
The character documentaries and tributes would be similar to the Behind The Tunes featurettes on the Looney Tunes Golden Collection. They would include interviews with many people involved with the show. Maybe Sesame Workshop could get some outside fans involved with the interviews as well. I would have these last an average of five minutes per documentary (some would be longer, some would be shorter).
It would be good if Frank Oz could be interviewed for features like these. I am sure that he would want to talk on the Jim Henson tribute, and maybe also on tributes that have to do with his characters. Clips of Jim Hensons characters would be used in the jim henson tribute, the other tributes would have clips from their works, and the various character documentaries would have various clips featuring those characters, including clips that aren't on the DVD.
The Big Bird documentary could include comments from Caroll Spinney, Matt Vogel, Lorretta Long, Bob McGraph, Sonia Manzano, Martin Robinson, Jerry nelson, Frank Oz, and Joan Ganz Cooney, for example. The Jim henson Tribute could have interviews with Jim Hensons family, Frank Oz, Jerry Nelson, Fran Brill, Bob McGraph, Roscoe Orman, Emillio Delgardo, Steve Whitmire, Kevin Clash, Joan Ganz Cooney, and possibly some people who never had a chance to work with Jim henson, like Eric Jacopson and John Tartiglia (and of course many fans of Jim Henson). After all, Eric and John are probably fans of Jim Henson.
Maybe Christopher Finch (author of Of Muppets & Men, Jim Henson: The Works, and some Dark Crystal book) and David Borgenecht (author of Sesame Street Unpaved) could be interviewed as well (assuming that they are still alive).