Hi,
I was looking for something similar as it is good to benefit from the public forum features while staying private :
-For user names
There is a plugin though but I haven’t tested it yet Always-Anonymous Categories Plugin - #42 by joo
-For full names
From what I understand, you can hide full names but only for everyone except admins with the setting : enable_names
This discussion here is interesting as the following user looks to be working on implementing a per group visibility of the full name feature : Disabling "enable names" makes admin act strange - #40 by mdoggydog
Don’t hesitate to udpate if you find an update on this feature or if a plugin is published. And by the way if you are looking to improve pricacy, this hidden setting is useful to prevent searches from anonymous users