Setting sas.logon.initial.password sets the password for the initial user account, so you don't need to go through the process of setting it using the reset URL in the SAS Logon Manager log.
Setting sas.logon.initial.user sets the username for the initial user account (this is "sasboot" by default).
So these settings are modifying the user ID and password for the initial "sasboot" user, you wouldn't be logging in as this user instead of sasboot, you would be changing the sasboot user ID to something else. It would still be a single, internal account.
Setting sas.identities.administrator lets you define a member of the SAS Administrators group in sitedefault.yaml. This is not necessary for the initial user. In my environments I set this to my personal user ID as well as passing in the LDAP configuration, so I never need to log in as sasboot.
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Greg Wootton | Principal Systems Technical Support Engineer