To summarize, Disney began work on a sequel to Tron: Legacy immediately. Legacy was meant to kick off a larger universe of movies and TV. As time went on, other expected hits flopped, and Disney acquired Star Wars and made it their new darling, the Tron sequel got shelved.
Jared Leto, who was going to have a minor role in Tron: Ascension, pushed to have a new movie made anyway, making his character the star. The result is that what was more of less going to be the third act of Ascension was fleshed out into a whole movie minus Sam Flynn, Quora, and Tron.
Imagine if Return of the Jedi was never made. Instead, the third act of the movie, the attack on the second Death Star, was turned into a whole movie but the continuation of the plots involving Han Solo, Darth Vader, and Luke Skywalker were completely cut out. Then Wedge Antilles was made the star of the movie and he personally confronted Chancellor Palpatine and saved the galaxy. That’s pretty much what has happened to the Tron franchise. :(
Edward Dillinger jr was played by Cillian Murphy in an uncredited role. The character didn’t exist.
Tron was also non existent in legacy. He had a single line.
None of these storylines you are talking about existed. A post credit scene is fluff.