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.
http://www.xuenay.net/Papers/CoalescingMinds.pdf
Like my other draft, this is for the special issue on mind uploading in the International Journal of Machine Consciousness. The deadline is Oct 1st, so any comments will have to be quick for me to take them into account.
This one is co-authored with Harri Valpola.
EDIT: Improved paper on the basis of feedback; see this comment for the changelog.