Would sensory prosthetics be the kind of thing you're looking for? I can add some cites about those.

Yes, they complement this nicely.

they seem to me like problems that could be eventually overcome

Well, destructive uploading as a whole seems to be a problem that could be eventually overcome, so with this approach you could discuss the upload-first scenario before the neurological one.

About dynamics of distinct-brain merge via exocortices - maybe you could mention what existing knowledge and what possible experiments could help answering these questions in the article.