Try every possible boot option. Previously, I was able to boot Windows from my C: drive called Windows-Main, now I have to boot from my D: drive called SYSTEMRESERVED. The macOS Disk Utility tool likes to mess with your other drives too for some reason.
You can (and the rules even suggest) play legacy as vanilla pandemic, just don't add any legacy elements. You'll be slightly limited by what characters you have, but that's not a big enough deal that I would buy the original if you're going to get legacy anyways.
Regarding the legacy edition is there any difference between red and blue