Well, if schizophrenia can exist, I'd say that was evidence that it was possible, and I mean true schizophrenia, two seperate personalities in the same mind, not the more common version of someone trying to escape into an alternate personality. It shows the Wetware can, in certain cases, keep two completely different perspectives in the same unit (the mind).
I agree with the 'E' that it's not Telepathy, more like 'Networking', or possibly 'User Accounts'

Also, I bet there's a difference between being connected like this since birth, and retrofitting this.
Agreed, the fact the brains
grew in that state probably account for the compatibility to a large extent, the brain simply worked with what it was given from a blank slate.