Ok Ezra,
1. To make your page all one width (I went with the width of the top image)
.entry-content, .entry-summary {
width: 791px;
}
2. To make all your menu items uppercase, even if you add new ones (fancy!)
.main-navigation a {
text-transform: uppercase;
}
3. You can't, that's a violation of the ToS, and would get Marielle's blog suspended.
4. I'm not sure how to make that two columns because the different paragraphs don't have different classes. Perhaps if you could class the first half of the paragraphs manually and do the same with the second half, you could then float the first half left, and the second half should zip up to the top (or do vice versa and float right on the second half). Little more manual work.
5 (comments). Go to your page in edit mode. Click on the tab at the verrrrry top of your browser window that says "screen options" (it'll be kind of below your name/search in the WordPress bar), and choose "discussion" from the check boxes. Scroll down your page to where you now have a discussion area, and uncheck the boxes.
Good luck!