Auto-provisionning ldap users and auth id?

My organization uses a samba ldap directory, which is connected to seafile server. We were using seafile since the beginnings, with a server-side seafile client on our samba fileserver (I made a patch few years ago allowing uid/gid changes by library). But this solution has some limitations, the main one being the duplication of all the data between seafile server and samba server.
I made some tests with seadrive, and the results are very promising, so i’m investigating in replacing some sambe services by seadrive.

I want to deploy seadrive on windows clients for all usersof my domain. I have two questions :

1 - is there a way to provision directly all my users into seafile, whithout the need of a first login to be registered, for example to be members or groups or added to shared libraries ?

2 - is there a way to generate user’s authid programatically, allowing generation of seadrive preconfigured profiles packages distributed by GPO, for example.

In other words, is there a kind of delegation for authentification, allowing admin to to generate user’s authid without having to access user’s password ? my domain is already synced with Google Apps for education, so using Oauth may be an option, but if possible I’d prefer an internal solution, not relying on external services.