You know, I just noticed two things. The creators violated their own rule in the Jay Leno short. Normally, they key to Kenny is that everyone in the show can understand what he's saying, but not people outside the show. However, in the Leno short, Stan had to interperet what Kenny was saying for Leno. Now, I know the RealLife(tm) reasons for doing this (the people who originally saw it, i.e. the viewers of The Tonight Show, might not have been viewers of South Park, and wouldn't have gotten the joke), but there had to have been a more true-to-the-show way of dealing with that.
Also (though I haven't seen the video version, I've only heard the mp3 version), it doesn't sound like Kenny dies in "O Holy Night." That will make Oholy the first short OR episode where Kenny doesn't die. (Even in Frosty, "Kenny" dies, even though "Kenny" is the name given to what is now Cartman)
Any comments?