While configuring authentication services the administrator and root user accounts were used. Does resetting or changing them have any impact on Authenticaton Services?
While those accounts might be used to set and establish the configuration they are not stored anywhere within the software. When a machine is joined to AD the computer object is created and a secret password is stored within a keytab on the host with limited permissions. This keytab is then used for day to day operations.
Resetting other accounts like root or administrator will have no impact on Authentication Services.