I have created a form for my organization to edit email aliases that requires the user to enter the users to add or remove from a multi-pick list. These are two separate lists but they have the same problem: 

This pick-list is extremely easy for the Requester since they can just enter the username and then it'll add the Requester's name to the list. However, once this list is made it only shows the display name for the Technician and gives no way to view the usernames for those entered into the pick-list.

I so far have not found a way to pull the email addresses for those entered in the pick list so our assigned technician can fulfill their role since they have to have the email address to add the user, requiring them to use a separate tool to look up their email based on the display name

For example, if the user's email address is jdoe@example.com the pick list will just show [John Doe] and does not show the email at all