The System - Cache plugin just needs to be at the end of it's group (System). Your image looks correct for ordering there.
For the buttons showing up in a line, I just looked a little further, and the Disqus module isn't displayed in a 'block'. It does have a div after it with a class of "clr", but that's not defined in your CSS file anywhere. Therefore, any contents after the module will show up to the right and will wrap if too long. It looks like if you add the following code to your CSS file, it will fix the wrapping issue:
The best guess location for this, if you don't have a preferred CSS file, is: /templates/yoo_downtown/css/style.css
Finally, for the Tweet button, there's a minor bug if both JFBConnect and JLinked are installed. It's easily fixable if you order the JFBCSystem plugin ahead/before (lower number) the JLinked System plugin. That will hopefully fix that issue, and may fix the JFBCGraph tags showing up.
Hope that gets you going, but as always, if not, just let us know!
Thanks,
Alex