All 23 of the 24 episodes will be in this collection. Wednesday Is Missing won't be included for whatever reasons 14 years later. Most likely what the cause is that WB either doesn't want or can't pay Carolyn, Jackie, Ted, and John's estates for their voice licensing as well as paying MGM for the original TV series. The Addams's were drawn like Charles Addams New Yorker comics, but their voices and mannerisms were that of the 1964 series.
Bottom line WB isn't paying someone what they want for this episode so it still can't be released.