I think it's fairly important to note that they're NOT currently using the microservice for the 2FA, and they're NOT using bcrypt right now.

The blog post states they're "working towards" these changes, they're not currently in place. It's fairly unlikely that they're using the same secret key as the one they found on the server, but it's fair to assume that they are still using salted SHA-2 for your passwords and the same 2FA setup right now.

They likely won't roll out the major changes until they roll out the "new and improved" Linode dashboard they're coming up with.