Option 4) Goat chooses a new exchange. Nefario works with that exchange to replicate the shares and accounts necessary for Goat to continue operating his assets.
Occurred to me, as I keep getting PM's asking us to setup a BTC version of litecoinglobal.com. I think all I'd really need is email addresses and share counts.
I would consider this (that does not mean i agree to it). However the asset/code holders would have to consent to being moved over and Nefario would still have to remain liable for code transfer issues and problems.
Nefario would clearly have to trust the new exchange.
Assuming Nefario is able to privately transfer the email addresses, the double spend issues go away because the new exchange emails everyone their new passwords. Any sharing that goes on is the sole responsibility of the new account recipient at that point.