Given scene/plot descriptions from movies or TV shows, and given a specific question about the scene, summarize the question into a title

I'm watching old episodes of Batman: The Animated Series on Amazon.com, and I notice several of them have, instead of the iconic B:TAS opening, an opening featuring Superman. Is there any difference in these episodes? Are they remastered or anything? Or is it just random choice on Amazon's part?   For example, on Amazon streaming, the pilot episode "On Leather Wings" had the opening featuring Superman, while the next episode, "Christmas with the Joker", had the one I expected. There were a few others with the opening featuring Superman as well, it seemed somewhat random.   ETA: This opening:    Vs this one:     ETA 2: "Fear of Victory" had yet another opening, featuring Robin. I give up. Amazon Prime is bizarre.
Why do some of the Batman: Animated Series episodes feature the Batman-Superman opening?

In Breaking Bad, Mike clearly calls Jimmy by his alternate name "Saul" multiple times. In Better Call Saul, we see that their paths are crossed quite considerably before Jimmy even starts using his alter ego of Saul Goodman.  Why does Mike entertain this alter ego name? He doesn't seem to be the type of guy who would do so, regardless of Jimmy's reasons for using it. It seems to be a bit of a plot hole (granted, it isn't a big one). I can see why someone would disagree with me on this point, but Gilligan's style is so careful and thought-out that it's surprising that something like this would be left unturned. Concepts of Better Call Saul were thought of well before Breaking Bad had finished airing, so I would've thought they had plenty of time to close any of these holes.
Why does Mike call Jimmy "Saul"?

In the movie Trainspotting when Mark "Rent Boy" Renton reads Diane's letter and Begbie arrives at his room, how did Begbie come to know where Rent was living?

How did Begbie track Rents?

