...uh, moving to number 2, sorry about the length of that last one. I'm not sure if we really have what psychologists call a core personality; or, if we did have a firstborn, they haven't fronted in years. What we usually did was to switch frontrunners every few years, and someone else would become the new 'main person.' However, it wasn't until 1998 or so that Azusa started to block others completely from coming out-- before that, people had come to the front involuntarily for short periods, or been co-present sometimes. During the years when she was in charge, though, there was a shutdown on the whole system whose extent we didn't realise until years later-- nobody could really get to the front, and new people couldn't enter the system.

3. When I mentioned switching frontrunners every few years, it was similar to the situation you describe-- the 'new person' would get access to the collective memories, although not the knowledge of how to act like the 'old person'; we were constantly being told things like "I don't know what happened. You just started acting so different."