Just a follow up ... have been successful in bulk user upload of a set of teachers accounts that authenticate via the plugin .
"username","password","auth","email","firstname","lastname"
username is sequentially numbered like so: social_user_1, social_user_2, etc.
password is left "" (ie, blank/empty) it will not be populated by authenticating vs Google anyway.
auth field is 'googleoauth2' for all.
There are options in importing now to allow duplicate EMail address which you might have to turn on if teachers already have existing accounts.
So it's doable ... even if manual.
'spirit of sharing', Ken