Is it possible to make the registration plugin work when using (read-only) LDAP? Technically my LDAP users (Windows AD, but could be anything) already exist so none of the events in the registration plugin occur. If you could do all the same things for users who are logging in for the first time (since that information is available I believe) instead of registering that would be ideal.
That, or have a default group whose members are users who do not belong to any group at all and which group is only shared with admins, who when seeing them would place them in their appropriate group(s). “New” users could automatically fall into this group.