I enjoyed here how the concept of a single person with multiple entities was explored. The concept of ancillaries was somewhat alarming, but it was stated clearly that that was problematic.
Dollhouse dealt with this to some extent, but there there were independent consciousnesses that diverged once the imprinting process happened. Each individual had faith that others existed so didn’t mind getting destroyed. I’m not sure that that’s how the individual would actually feel, though. There is much written in philosophy about this.
Here, though, while there are separate appendages, they are all linked and aware of each other, not unlike nodes in a distributed database.
After reading The Singularity is Near, I do think more about how merged minds would work. Ultimately there would be some loss of self.