HSDL Defaulting Values based on other values for External Data

I'm trying to make an HSDL more user friendly. For example, the users are not entirely familiar with assignment_number or person_number therefore they want to search by name and also be able to see the name in the spreadsheet upon entering data without having to take extra steps (I've prototyped using filter criteria to force a single select for a user…).

Is there a way to either Default the assignment_number based on a selection of an Employee Name while still displaying the name to the user? Is there a way to display the employee name in the spreadsheet while sending the assignment_number as the key value upon Save/Upload?