But if I use yum can I still install the webmin rpm and the webmin turtle firewall sepeartely or before I start yum? Without a graphical interface to tell me what packages are included in yum I have ...

I've always had problems installing/updating Webmin from apt. It's a lot easier (in my experience) to just download the tar.gz from the website, run the included setup script, and let Webmin update ...