As for the answer, the answer is nothing, since it's a spoiler. The character is already known by one name, any later names that are spoilers won't be used, unless we can't avoid using it.
Also who is to say there is only one core present on U-2501? As stated a Destroyer-class core can't control a ship like U-2501, so there is another core involved, either one on board or remotely (at minimum Musashi is heavily hinted at being involved). If another core is on board though, then there is the possibility this mental model isn't from Z1's core. Even more so when you consider that a destroyer can only form a mental model through having another ship pick up the processing slack.