How to get Financial Reporting Users Usernames or User IDs

I am looking for Financial Reporting User IDs (like SAM Account Name). In the Planning Relational Databases this info is stored in HSP_USERS and HSP_OBJECT. Is there anything similiar to this for FR users? I am looking to extract a list of FR Users by ID and the Users authenticate using MSAD.

I have come close to this info in the CSS_IDENTITY table, but this table does not store the username/user id. If I were to resolve the MSAD GUID to a username, could I store it in CSS_IDENTITY.NAME column; I'm not sure if there are any other columns dependent on this. Is there a database setting that would 'auto update' the NAME column when a user authenticates?