Hey Jason McCann,
Do you think you could use the following - to remove the NULL data - or is the issue that you would like these data in there, however they are displayed as NULL?
IFNULL([Field Containing The Null Literal], 'string to replace the null literal')
It's not so much that displaying NULL is a problem. I'm more curious as to how/why these records are NULL, because if I log in to Tableau and view a workbook, the record in PostGRES is populated with my user friendly name. With Guest account disabled, it is my assumption that all records should contain a user friendly name