I have enabled all show options in the Back End (Registrant Username, Date Registered, Avatar, List to Profile, Expansion for Groupmembers) but I only see in the Front End: Empty column, First Name, Last Name.
This is normally a setup issue. First, make sure you've upgraded to the very latest version, 2.8.2a as of Tuesday, so we eliminate any known issues.
Second, submit a ticket so we can take a look at your settings to pinpoint the problem.
Usually it's a permissions thing. Sometimes users belong to multiple groups in Joomla and this causes that user to be unintentionally restricted. Also often after an update, users need to go in and save permissions or events if they are affected by the changes/upgrades.
We can help you sort it out if you enter a ticket.