This probably isn't "news" but I noticed in researching my Holiday Special review I found that Starwars.com's Databank openly acknowledges things from the Star Wars Holiday Special as cannon.
QUOTE
With the rise of the Empire came a terribly dark time for the Wookiees. At the advice of unscrupulous Trandoshans, the Empire blockaded Kashyyyk and enslaved the Wookiees, using their brute strength for labor. So devoted were the Wookiees to their homeworld, that many would brave the blockade to revisit their cherished forests for key Wookiee holidays.
I thought this odd considering Lucas's contempt (justified) for the Holiday Special and his efforts to erase it from existence.