These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
This can often be for any of the characters and relationships, since each production and country does it slightly differently, e.g., who Victoria does her "Sexual Awakening" dance with, who Alonzo gets paired with (Demeter or Cassandra), and which cats are in the cast, often "Swing Kittens" like Etcetera, and Electra, or the London Swings (e.g. the 'Brown Queen') can be left out (due to some of them originally being actors/actresses other cats characters outside of songs (Rumpleteazer/Etcetera, Quaxo/Misto for example), so Rumpleteazer and Tantomile can be members of Rum Tum Tuggers screaming fan club. What fans use as "their canon" can depend on which country they're in, which productions they've seen, and whether they own the filmed stage version.
The Rum Tum Tugger and Mistoffelees are a particularly confusing instance. RTT sings Mistoffolees' song, and it's commonly accepted that they're friends, at least until you remember that in RTT's song the chorus goes "The Rum Tum Tugger is a-" and Mistoffelees shouts "...terrible bore!" Fans are divided on their relationship with one another.
Word of God says that Mistoffelees and the Tugger are two of a group of four brothers (the other two being Munkustrap and Alonzo), and this forms the basis for their love/hate relationship. It also explains the reactions of Munkustrap and Alonzo to the Tugger and Mistoffolees, and vice versa.
Alternate Character Interpretation can also be caused by who is doing what part. For example, one critic compared Betty Buckley's Grizabella to Elaine Paige's Grizabella as follows:
"When Buckley sings "Memory", Grizabella is burdened by regrets about the life she's lived, having spurned all those who once knew her for her days of glamour and now wants to reconnect with others as a form of redemption for her betrayals. Paige's performance, however, is a lonely, lost forgotten star who is now past her prime, and simply wants someone to remember that she was there."
A common interpretation is that the play takes place in the afterlife — Jellicle being "'gelical", or Angelical — and they recount their mortal lives as a reason they should be allowed to be reincarnated.
It can be argued that the whole thing is about Sanctification by Grace; the cat who is chosen to be taken up to the Celestial Lair isn't the clever Mistoffeles, the charming Rum Tum Tugger, the wise Deuteronomy, or even Jennyanydots with her good works — it was Grizzabella, mangy, skanky Grizzabella, the cat who NEEDED it most.
Ho Yay: Here and there, but mostly between Mistoffolees and the Rum Tum Tugger.
Jerk with a Heart of Gold: The Rum Tum Tugger maybe a casanova who breaks hearts as often as he steals them from the female jellicles, but he shows great respect to Deuteronomy (believed to be his father) tells the others how to bring him back when he's kidnapped, and at the end of Mistoffeles, gives all credit to him when Deuteronomy asks who if he brought him back.
Les Yay: Deme and Bomba, anyone? Though this leads right into squick territory if you consider them sisters or not.
The ending of "Gus: The Theatre Cat" where Gus, longing for the bygone days of his youth and fame, breaks own into tears, unable to choke out the last part of his song, and is led off the stage, sobbing. Doubly so in the video production, which was one of the last performances Sir John Mills gave before he died.
The notoriously heart-wrenching "Memory". Grizzabella is a hideous mess, and she knows this more than anyone, but just wants the others to show some kind of sympathy for her.
"Now the Peke, although people may say what they please, is no British Dog, but a HeathenChinese." It is understandable because the lyrics were written during a time when they would have been considered acceptable. However, since other Unfortunate Implication lyrics were changed during the course of the show's run (e.g., original lyric "The Chinks they swarmed aboard" was changed to "The Siamese swarmed aboard), this could probably have been avoided.
Black actress Femi Taylor playing a cat named... wait for it... Exotica.
Values Dissonance: Macavity's habit of cheating at cards, which now reads as Arson, Murder, and Jaywalking, was never a criminal act, but it was once an extremely serious social offence. In the nineteenth century, accusations of cheating could and did lead to duels.
What Could Have Been: Femi Taylor, who plays Exotica in the film, once played as Bombalurina during a variety show, singing "Macavity". Unfortunately, she is completely missing from the song in the video.