I have done some testing on my localhost, and I am able to set up fields that are hidden for users, and only visible to the superuser. Just what I needed. I had one experience where all user fields were blanked, and only the name was remaining. It may have something to do with the default plugin "User - Profile" which I later deactivated. So I am using only the standard Joomla user fields, plus EasyProfile extra fields.
You wrote:
Yes and no, you can see all fields on backend, but not in list. Easy Profile extends Joomla User Management, this is great but have some limit.
Can you elaborate here? What list are you thinking about? What limits are there?
Now, before committing to EasyProfile as backend user management, can you at all tell about your future support for EasyProfile? I am thinking in case Joomla gets upgraded and EasyProfile breaks.
By the way, I can edit all other posts...
Settings for "hidden from user fields" attached.