You do not seem to have attached any images to the post which contains the gallery as your gallery's XML file contains no images: http://wwwsevenarrows.zippykid.it/wp-co … ebox/2.xml

It looks like you may have clicked 'Insert Gallery' on the 'Add Media -> Gallery' tab.
This refers to a WordPress gallery and has nothing to do with Juicebox but may account for the images above the Juicebox gallery on your page.
After adding images, clicking 'Save Changes' and being redirected to the 'Gallery' tab, simply close the upload window and publish or update the post.

It is not possible to add non-gallery elements of your web page to the gallery's overlay.

Yes. You can upgrade WP-Juicebox from Juicebox-Lite (which it comes bundled with) to Juicebox-Pro and then customize your gallery with Pro Options by following the instructions here.
It you have already created a gallery with JuiceboxBuilder-Pro and wish to know what settings your gallery uses, open up your gallery's 'config.xml' file in a plain text editor.
The settings are the attributes to the opening <juiceboxgallery> tag.

Yes.
(1) Create your gallery with JuiceboxBuilder-Pro
(2) Upload your complete gallery folder (not just the contents) to your web server via FTP using a program such as Filezilla
(3) Create a new post and use the baseUrl method to embed your gallery (ensuring that the method of entry in your post is 'HTML' rather than 'Visual')
For example, if your domain name is 'www.example.com' and your gallery folder is named 'my_gallery_folder' and you uploaded your gallery folder to the root of your web space, then the embedding code you would enter would be:

<!--START JUICEBOX EMBED-->
<script src="http://www.example.com/my_gallery_folder/jbcore/juicebox.js"></script>
<script>
  new juicebox({
      containerId : 'juicebox-container',
      baseUrl : 'http://www.example.com/my_gallery_folder/',
      galleryWidth : '100%',
      galleryHeight : '600'
  });
  </script>
<div id="juicebox-container"></div>
<!--END JUICEBOX EMBED-->

Alternatively, you might like to try the dedicated Juicebox plugin for WordPress - WP-Juicebox.

The Lightroom plugin can be updated from Juicebox-Lite to Juicebox-Pro by following the instructions on this page: http://www.juicebox.net/support/lightroom/
Please note that upgrading the plugin will not change the interface within Lightroom and the 'Upgrade to Juicebox-Pro' button will still be visible.
However, the Juicebox badge (at the bottom-right corner of the live preview window) should be gone, indicating that the plugin is using the Juicebox-Pro files.
You can add Juicebox-Pro Config Options to your gallery created with the Lightroom plugin by either:
(1) Opening and editing the gallery with JuiceboxBuilder-Pro, or...
(2) Opening the gallery's 'config.xml' file in a plain text editor and manually adding the Pro Options as attributes to the opening <juiceboxgallery> tag

Your audio now plays in Firefox 13.0.1 on my PC.
Try clearing your browser's cache before reloading your gallery.

Your audioUrlMp3 and audioUrlOgg are currently:

audioUrlMp3="http://www.robertmunozphotography/music/SymphonyNo6Movement5.mp3" audioUrlOgg="http://www.robertmunozphotography/music/SymphonyNo6Movement5.ogg"

They should be:

audioUrlMp3="http://www.robertmunozphotography.net/music/SymphonyNo6Movement5.mp3" audioUrlOgg="http://www.robertmunozphotography.net/music/SymphonyNo6Movement5.ogg"

Try launching Lightroom, then go to 'Lightroom -> Preferences', select the 'Presets' tab and click the 'Show Lightroom Presets Folder' button.
The presets folder should open up in a new window. Now go into the 'Lightroom' folder and either go into or create the 'Web Galleries' folder there and then copy 'juicebox.lrwebengine' into the 'Web Galleries' folder.

What was the location where you created your 'Web Galleries' folder?
The instructions on this page should be accurate for Lightroom 4 (which is required for the plugin).

Juicebox works fine alongside a Facebook Like button.
There are a couple of things to bear in mind, though.

(1) If you are trying to insert a Facebook Like button into the 'index.html' page of a 100% x 100% gallery, the gallery will take up the entire browser window so if you place the button after the embedding code, it will be pushed off the bottom of the browser window and will not be displayed. You would need to either reduce the size of your gallery to accommodate the button or position the button on the page via CSS and give it a high 'z-index' value (so that it is stacked above the gallery layer) in order for the button to be active.
For example, if using the HTML5 implementation of the button, you would change the line:

<div class="fb-like" data-href="http://www.example.com" data-send="false" data-width="450" data-show-faces="true"></div>

... to:

<div class="fb-like" style="position: absolute; top: 50px; left: 10px; z-index: 999;" data-href="http://www.example.com" data-send="false" data-width="450" data-show-faces="true"></div>

(2) The button will be displayed only when your web page has been uploaded to a web server. It will not be displayed when you preview your web page locally in a browser on your computer.

On a regular web page, the 'maximum-scale' setting determines how far the user can zoom into the page.
In a 100% x 100% or expanded Juicebox gallery on a mobile device, this value is automatically set to 1 which is why you see no difference in removing it.

What device and version of iOS are you using, and could you perhaps upload a screenshot somewhere? Thank you.
I have tried Chrome on my iPod Touch 4 iOS 5.1.1 and a standard gallery (such as this one) is truncated at the bottom due to the address bar at the top but it does not sound like the pixel density issue you are experiencing.