I have integrated wpFORO with Memberpress and the display names for members is automatically created as their First and Last names when they register for my website. Is there a way to remove this to give people privacy? Or only display the nicknames instead of display name. I don't want their first and last names to be visible to other's on the forum.
That comes from the plugin you are using, wpForo doesn't set user's display name by their First and Last Name, Please read the Below FAQ Topic about Nickname, Username, and Display Names: