There were plans to remove the 2-C bit as I heard
@JoshSSJGod was looking at some Xenoblade Chronicles X files that outright state that some Phase Transition Event outright created an Endless number of Universes. The game mostly just said an Endless Number of Universes exists rather than outright saying it created. But we know it created at least three given XB1, XB2, and XBX are all three separate universes created by the same event with the mention that many people and many things vanished into distant dimensions. Which implied it still effected many universes, but the XBX pages haven't been made yet and there were plans to make a blog post elaborating everything that wasn't tackled much yet.
But XBX does confirm the entire multiverse is pretty much created by the conduit in the extended files from what I heard. As for why there's a 2-B end, it's because some people are cherry picky on the word "Endless" as opposed to "Infinite" because some dictionaries use it as a synonym for nearly limitless rather than outright limitless. But it was agreed to accept At least 2-B, possibly 2-A for various "Endless universes" statements.