This is not part of the data I have in hand - I though of setting the same dummy password for all but someone could easily hack in if they knew what the dummy password was. My issue now is that we are trying to encourage people to log in with the University log in module that doesn't use the default email + password stored in Drupal. I am not sure how to get these migrated users connected to that third party log in module instead.

Thanks @GaëtanFrenoy - I updated the description. It is a third party authentication module that I cannot update.