I have encountered occasions in a hybrid environment where some person documents don’t appear in SmartCloud so they are not available for addressing mail and are not available for provisioning, as in the case of creating a new user. The issue turned out to be that the entry in the Manager field on the Home/Work tab of the person document contained a long string of characters (about 40). This prevented the document from getting synchronized with the directory in SmartCloud. SmartCloud is designed so to avoid other problems, if there are any fields that can’t be synchronized, the whole document doesn’t.
So if names in your Domino Directory don’t appear in SmartCloud, review the fields for any unusual content that may be preventing it from synchronizing properly.