I can answer these 2 questions:

Quote Originally Posted by PaulBx1
5) I'm guessing regular Knoppix programs, like Konqueror, save things under /home, right?

6) Programs like Firefox do not, so Firefox bookmarks are not saved unless a replacement Firefox is installed under /home, right? And emails in Thunderbird, same way, right?

I'll be back to ask more, probably...
Allmost everything saves things under /home, even Firefox and Thunderbird.

If your username is "knoppix", then Firefox saves bookmarks to
/home/knoppix/.mozilla/firefox/*.default/bookmarks.html
where '*' is some random chars.

I don't use Thunderbird, so I'm not 100% sure where it saves the emails, but I'd quess somewhere in /home/knoppix/.mozilla