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)

The XML file used for the http://sandbox.castarchitecture.com/pro … homes.html gallery is not the one you quoted.
The gallery uses this XML file which does not set the two configuration options from my post above: http://sandbox.castarchitecture.com/pro … config.xml

If you want your gallery to use the http://sandbox.castarchitecture.com/TEM … config.xml file, then you can point towards it in your gallery's embedding code using a configURL configuration option or, alternatively, as your 'TEMP_JUICEBOX_FOLDER' folder seems to be a complete gallery folder, you can use a baseUrl, for example:

<!--START JUICEBOX EMBED-->
<script src="/TEMP_JUICEBOX_FOLDER/jbcore/juicebox.js"></script>
<script>
    new juicebox({
        baseUrl: '/TEMP_JUICEBOX_FOLDER/jbcore/classic/theme.css',
        containerId: 'juicebox-container',
        galleryWidth: '100%',
        galleryHeight: '100%',
        backgroundColor: 'rgba(255,255,255,1)'
    });
</script>
<div id="juicebox-container">
</div>
<!--END JUICEBOX EMBED-->

If you do not specify either a configUrl or a baseUrl, Juicebox will look for a file named 'config.xml' in the same directory as the page containing the embedding code. In your case, there is such an XML file in that location but it is not the XML you want your gallery to use.
(Alternatively, you could replace the http://sandbox.castarchitecture.com/pro … /config.xm file with http://sandbox.castarchitecture.com/TEM … config.xml on your web server.)