What about that whole rope analogy?
It's still unclear. Unfortunately, Selebus has the habit of dropping imagery and not making it clear if he stopped using them because they've been revealed or because he simply forgot about them.
At first glance, the rope seemed to be Pareidolia because at that point we only knew of Wires (nothing/darkness) and HOPE (everything/light). So, when they say there's a third player in this tug of war, that is the rope, and that it has a mind of its own - it would be logical to assume that it is USER3.
But then Pareidolia started to be confused with aspects that should have been Wires', like the darkness. And our Akira was called out for being a fraying thread of a much more complex rope (presumably the amalgamation of every Akira).
Since Selebus dropped the rope analogy, it remains unclear. Best guesses are either Pareidolia or Akira himself, but there are others, like shadow Maya or the world itself. There is an event called "first signs of fraying threads" that has Ami freaking out on Maya, and that is hard to justify if the rope was either Pareidolia or Akira, but it makes a lot of sense if the rope refers to the world itself. Anyway, we don't know.
Also is there a reason why they're all named after adjectives starting with C or is it a "C"oincidence
Not that we know of. Since it's four points of a cross, it could be the C from cross, or Christ.