Regarding a delay on starting firefox (3) There are two ways that
should work. However, I have never had luck with the first. Maybe
someone can clue me in as to why.

1) go to System -> preferences -> startup applications -> add

Then type "sleep 30 && firefox &" into the command box... But maybe
the problem is the launcher is not in a bash shell?

2) What has worked for me:

make a script by opening gedit and typing the following

#!/bin/sh
sleep 30 && firefox &

(note that is a "# "and a "!" without any spaces between or after them
on the first line.)
Save script as something like "firefox.sh"

go in your terminal and navigate to the directory you saved it to,
then type "chmod +x firefox.sh" to make the file executable.

Now to test the script, either type ./firefox.sh, or doubleclick on
the file and select "run". If it is working properly, you should be
able to add the script to startup the same way you added your
application (i.e., System -> Pref -> Startup Apps -> Browse).