How can I change a rendered user display to a combination of fields linking to the user?
One option would be to use:
Real Name

The RealName module allows the administrator to choose fields from the
user profile that will be used to add a &quot;real name&quot; element (method)
to a user object. Hook_user is used to automatically add this to any
user object that is loaded. It will also optionally set all nodes and
comments to show this name.

For Example:


By default only the raw username is being shown, as you can see at the
top of the page.

Change this to:

Result:

source: Change Drupal Usernames with the Real Name Module