Wow this is incredible, awesome that you have it backed up as well; we would love to have the Mew preserved here whenever you can get them to your PC. To try and answer your questions, I'm not sure if any of those methods would work, but your best shot at trying to get a copy of this Mew would be the VC path you laid out, but even if that did work the Mew would not be considered "legitimate" as there is obviously no legitimate way to transfer from the original GameBoy cartridges up to Gen3+
We'd also love to have copies of the certificate of authenticity if you still have one, or even your picture at the event, feel free to blur out anything personal obviously haha!