When adding user account, cannot add member to group wheel or anything else

Hello Forum,

I think I may have enabled too many security features that prevent me from adding any user account to groups wheel and others during the installation.
I am not sure of how to get these back to not enabled post-installation. At least enabling the superuser account privilege for a normal account.

If somebody could please help with this situation with the configuration files. I'm awfully sorry that I am a newbie.
The moral of this story is, don't enable anything that is out of reach.
Hmm, without knowing what you selected during installation, it's going to be harder to figure out how to reverse it. If you are inexperienced with FreeBSD and continue down this path, I think you are going to get frustrated fast.
I would re-install with the stock options, where possible. At least make a note of what you change during the installation and let us know if you are still having problems.
All of the settings on the new (to FreeBSD 11 installation) security screen can be enabled and you will still be allowed to add a user to the wheel group, I know because this is how all my FreeBSD 11 computers are set up.

When you say you are prevented from adding users to other groups, is there an error? Or does the option to add them not appear?
Have you tried to edit /etc/groups file and add the user to the wheel group?

% sudo head /etc/group
# $FreeBSD: releng/11.0/etc/group 294896 2016-01-27 06:28:56Z araujo $
Never edit the files directly. Usually it's not a problem but sooner or later it's going to bite you. The group file is a little more forgiving but it's better not to edit it directly.

pw group mod wheel -m myuser