Hi there introuble!!!
I cannot answer all your questions but:
1) Go into /var/log/packages. There you will find all Slack packages installed
2) To remove a Slack package, go into /var/log/packages and type removepkg <package_name.tgz>
7) To you mean path? Usually, you simply export variables to your path. A very common question is adding Java to the PATH. it's done like this:
For some good hints about Slackware, I would recommend this link:
even securing Slackware is very well described in there!.
Good luck mate!