Hi,
"Visibility for" parameter set the visibility in the field list (not title). Title of page is not "Firstname" and "Lastname", this is a Joomla name (Format name), you can change this from Easy Profile options, the parameter is "Display Format Name"

This is actually not working completely. With the Display Format Name set to Username, I got some issues with other component's microcode like Corejoomla Forum which displays First Name Last Name no matter what. CJ Forum dev traced it back to the plugin Easy Profile Author plugin. What is this plugin doing? Can we de activate it?

Hi,

I got some issues with other component's microcode like Corejoomla Forum

This is normal, Easy Profile can't control output of others components. Anyway I think all Forum components have a option to display username instead Format name.

CJ Forum dev traced it back to the plugin Easy Profile Author plugin. What is this plugin doing? Can we de activate it?

read docs about this at http://docs.easy-profile.com/index.php/article/author-plugin. As written in docs this plugin is disabled by default.

Thanks. Deactivated the author plug and got the rest of my components working again with proper username display.