How to run HTTPD as specific user(s) and not by nobody?

The way to run httpd as a different User|Group is to change the user or group directive in the httpd.conf file.

User apache
Group apache

This though would only change the nobody in your output above to apache which I guess isn't what you want.

To have httpd run as a particular user you are going to have to create and manage a configuration file for each of them. The configuration file should specify the User and Group appropriately as well as the port the httpd process should bind to via a Listen directive. Remember only privileged users can bind to ports <1024. You can then start it like so

apachectl -f /path/to/aramis.conf -k start -DSSL

Note other httpd directives e.g. VirtualHost will likely need changing too on a per user basis.

Additionally EL variants (RHEL, CentOS Scientific Linux etc ) SELinux is involved. You will have to add the port that each instance will bind to, to the http_port_t group e.g.

semanage port -a -t http_port_t -p tcp 8888

which would allow an httpd instance to bind to port 8888.

If the users will use their home directories to serve files from then you will have to allow it with the httpd_enable_homedires SELinux boolean

 setsebool -P httpd_enable_homedirs on

The above should allow you to configure per user instances of httpd however each user will have to remember which port to use to add to their URLs e.g for aramis above

http://example.com:8888

This is all very messy. To help your users out you should configure your main httpd to listen on port 80 as usual and act as a reverse proxy to the per user instances. Then when aramis connects to e.g.

http://aramis.example.com 

the main server proxy's it aramis's instance.

You're going to have to configure the DNS and possibly other things appropriately too.