A little on the beginnings of these villains as presented in this issue (and a little more as well!).
In "The Killing Peck", Oswald was getting revenge on an old nemesis from earlier in his life, who tortured the boy who loved books and birds, making him eat fish and wear a suit, leading him down the route to becoming the Penguin in this story by Alan Grant and Sam Keith.
When is an origin not an origin? When it's "When Is A Door" by Neil Gaiman, Bernie Mireault and Matt Wagner, with the film crew following the Riddler through an old warehouse full of oversized novelties (once a feature of Batman comics in the 1950s), and the Riddler making odd commentary on it all, leaving his origins a question.
Two-Face was almost portrayed as a hero in the untitled story in the Special, by Mark Verheiden, Pat Broderick and Dick Giordano (and he is only a coin flip away from being one, after all). Still the district attorney who had acid thrown in his face by Boss Maroni, this story explored how Two-Face could be a hero, saving Grace (who was the one telling this Two-Face story to Steve Jones), and how he saved her from Dalton Perry (a criminal who was looking for revenge against Harvey, by kidnapping Grace).
first appeared in the Golden Age, only had Batman in common, but this Special started a slight link between them....something that has been built on upon the years, and continues to this day!