There are two relatively easy solutions to your problem. Either:
(1) Use an opaque (rather than transparent) expandedBackgroundColor. For example, try setting expandedBackgroundColor="rgba(255,255,204,1)" rather than expandedBackgroundColor="rgba(255,255,204,0.2)". This will ensure that no elements from your web page are visible when the gallery is expanded.
... or:
(2) Set expandInNewPage="TRUE" (in JuiceboxBuilder-Pro's 'Customize -> General' section). When the gallery is expanded from the Splash Page, it will be displayed on a page of its own rather than on top of the embedding page.

Use the following configurations in your galleries:
showThumbsButton="FALSE" (in JuiceboxBuilder-Pro's 'Customize -> Lite' section)
showThumbsOnLoad="FALSE" (in JuiceboxBuilder-Pro's 'Customize -> Thumbnails' section)

Please check the source of your web page in a browser to ensure that there is a div with id="viewsstyle--vista-galeria--default" on your page.
The Juicebox module for Drupal is responsible for creating the code which goes on your web page.
It should create a container for your gallery and embed the gallery into it.
It sounds like the container's id is being used in the JavaScript embedding code but that the container itself does not exist on your web page.

Please note that we did not write the Juicebox module for Drupal ourselves and as this query seems to be directly related to the module's code (rather than Juicebox itself), I would recommend that you post your query in the Drupal forum where the author of the module should be able to help you out further.

In the meantime, please post the URL to your web page. I will be happy to take a look and help further if I can but the author of the module (who is more familiar with its code than myself) is likely to be the best source of help.

You gallery online is a Juicebox-Pro gallery and the Juicebox branding is not present in the lower-right corner.
If you still see the branding, then please clear your browser's cache before reloading your web page. It sounds like your browser might have cached and be using the original Lite 'jbcore' folder which is no longer on your web server.

The Multi-Size Image Support seems to work fine but perhaps not as you expect it to.
If you are adding the extra image sizes to your gallery's XML file manually, the attribute names are case-sensitive so take care to use smallImageURL and largeImageURL entries (instead of, for example, smallImageUrl or largeimageurl).
Try opening an image in a new window (with the Open Image button on the Button Bar) and you should see the largeImageURL being used.

Each image (small, medium and large) in the Multi-Size demo gallery is unique. All three sizes for each entry have the same file name but they are stored in different folders and are different sizes (though I agree it can be hard to tell which image is being used just by viewing the gallery).

The logic used to determine which image to use can be found in the Multi-Size Image Support section.
To a certain extent, Juicebox does take into account the screen resolution. The size of images used in the gallery is partly dependent on the Screen Mode used to display the gallery and as long as screenMode="AUTO", the Screen Mode is dependent on the screen resolution (amongst other factors).
Unfortunately, it is not possible to change this logic (for example, to introduce your a custom screen resolution threshold into the mix). If you would like to suggest this for a future version of Juicebox, then please post in the Feature Requests thread. I do not know how likely it is that your suggestion will be incorporated into a future version of Juicebox but at least it will be in the right place and will not be overlooked by the developers.

An alternative to using Multi-Size Image Support would be to use a single image of high enough resolution that it would still look OK on the highest resolution screen that you expect your gallery's target audience to use. The image would still be dynamically scaled down appropriately for use on smaller screens.

I hope this helps clarify things.

This is possible only with Juicebox-Pro (not with Juicebox-Lite) by setting thumbsPosition="TOP". (thumbsPosition is a Pro-only configuration option).
For a list of all Pro Thumbnail Options, please see here.

That's great! Thanks for letting me know.

When expanding a gallery on an iOS device, Juicebox will expand the gallery in a new page by default (using the 'full.html' file) as if setting expandInNewPage="TRUE". Please see the Expand Gallery Behavior support section for details.

Expanding in a new page works only when the gallery has been uploaded to a web server (and not locally on your own computer) so everything should work OK once you upload your gallery.

Your gallery seems to function OK on its own (www.spoken-image.com/clients/7559LL/Gallery1/) so I suspect the problems are related to the other code on your web page.

When expanding your gallery and navigating between images, the main images seems to be pushed to the very right of the gallery container. This is likely to be caused by global CSS rules on your web page which the gallery has no option but to inherit and which may be interfering with the gallery's own CSS rules.
Your web page loads 12 external CSS files. Try temporarily removing them from your web page and re-introduce them, one-by-one (checking your gallery after each one), until you find the source of the conflict.

I think this may be due to one of the HTML errors on your page (an unclosed <script> tag).
Change:

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"</script>

... to:

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script>

Juicebox searches through the <script> tags on the web page to determine the 'jbcore' directory (in order to know the location of other files) and this broken script tag may be interfering with this process.

With regard to the Splash Page being large, all that can be done to reduce this in side is to reduce the dimensions of your gallery or scale your web page for mobile devices using the <meta> 'viewport' tag .

You can certainly use these images to create a gallery on your computer but you will need to upload the gallery's own images (inside the 'images' folder) to your web server in order for them to be publicly accessible.

Yes. As long as the 'Resize Images' checkbox is selected on the 'Images' tab, JuiceboxBuilder-Lite will resize your images.
You can click the 'Change Sizes...' button to set dimensions for the images but the default values will likely be OK.

The gallery's index page is required only if you want to display the gallery on its own web page and you can call the page whatever you like, it does not need to be named 'index.html'.
If you want to embed a gallery in an existing web page alongside other content, then you should use the embedding code and follow the embedding instructions here.

I've taken a look at the code on your http://www.foxsdengolfcourse.com/Pictures.html web page and if you want your gallery to appear on that page, then you would need to upload the contents of your gallery folder (not the folder itself) to the root directory of your web space. (Do not upload the gallery's 'index.html' file, though. It is not required and will overwrite your own 'index.html' file.)

Alternatively, try the following (using the baseUrl method of embedding which allows you to keep all your gallery files inside the gallery folder).

(1) Create an empty folder on your desktop and name it 'gallery'.
(2) Create a gallery with JuiceboxBuilder-Lite and save the gallery in the folder you created in Step #1.
(3) Upload the entire gallery folder (not just the contents) to the root directory of your web server (directly into your 'public_html' directory) using an FTP program such as Filezilla.
(4) On your 'Pictures.html' web page, use the following embedding code:

<!--START JUICEBOX EMBED-->
<script src="/gallery/jbcore/juicebox.js"></script>
<script>
  new juicebox({
    baseUrl: '/gallery/',
    containerId: 'juicebox-container',
    galleryWidth: '100%',
    galleryHeight: '600',
    backgroundColor: 'rgba(0,0,0,0)'
  });
  </script>
<div id="juicebox-container"></div>
<!--END JUICEBOX EMBED-->

@wspollack

No. jAlbum has the ability to save a project's settings (very much like saving a preset in JuiceboxBuilder-Pro) which you can then apply to a future project.
However, there is no such functionality in the Juicebox plugin for Lightroom and you cannot load an existing Juicebox gallery in Lightroom to edit it (which, if it could be done, you would do to simply load the configuration options and ignore the images).

Modifying the plugin's 'config.xml' file is probably the easiest way to ensure that certain configuration options are applied to all galleries created by the plugin.