Yes you can create the users but the invite system requires email near as I can tell. So to be more precise I manually created the users, sent the invites (which failed because of mail configuration), logged on to their accounts. There is no indication that they are in a share that they have been "invited" to. When logged in as the user if you issue a "request to join" the share I don't see anything on the admin side either.
It looks to me (a new user/installer) as though the workflow requires a working email connection or you basically can't do anything. Seems strange that you couldn't do this manually since that wouldn't be an unusual use case in an enterprise(?)
Maybe I should try private instead of moderated?