not sure what you are describing there.
I see nothing like
ACP/messages/cnfg. client, cnfg. email/
contact email
source email
in the admin panel.
however, there is a section called email settings.
there put your board email in both blanks.
also, you should probably use your board email for your admin account email.
choose no for the setting to use smtp unless you have a specific reason to set it to yes.
the only thing close to a "super user" is the founder account that the person who installs the board has.
the founder account has access to everything. when you install you are also put in the global moderator group.
the only thing that being an admin or being in the administrator group does is give the user access to the admin panel.
and yes, you can create as many accounts as you wish. you can then put them in whatever groups you wish.
you can make someone an admin by putting them in the admin group.
you can make someone a moderator by putting them in the moderator group.
you, as founder, can also make someone a founder.
remember, everyone that is registered is in the registered user group.
then people can be put in or removed from other groups as needed.
robert