Unfortunately, JuiceboxBuilder-Pro is able to extract only the IPTC Document Title (for use as the image title) and the IPTC Description (as the image caption). (Just go to 'Images -> Titles -> Use IPTC Title' and 'Images -> Captions -> Use IPTC Caption' from the drop-down menu at the top.)

Currently the only automated way to extract any other embedded metadata from images would be to use the Juicebox Lightroom Plugin.
If you are an Adobe Lightroom user, you can use the Juicebox Lightroom plugin to create your Juicebox galleries.
Lightroom has the ability to extract whatever metadata you like from an image (EXIF or IPTC) and the Juicebox Lightroom Plugin can make use of this for the image titles and captions.
Once the plugin has been installed, you can select the Juicebox web layout, scroll down to the 'Image Info' section, choose 'Edit...' from the drop-down menu (for the image titles and/or captions) and you'll find the functionality for extracting metadata there.

You can certainly have some custom text in your Juicebox-Pro galleries.
If you wanted some text for the gallery as a whole, then you could use the galleryTitle (in JuiceboxBuilder-Pro's 'Customize -> Lite' section). You could position the Gallery Title using the galleryTitlePosition ('Customize -> General) and, if you like, you could even style the Gallery Title using HTML formatting as noted in this FAQ:
How do I add HTML formatting to the Gallery Title or Back Button?

If you wanted some text for each individual image, then you could add image titles and captions.
Click a thumbnail image on the 'Images' tab and the input boxes for the image titles and captions will be revealed. You can enter custom text there (or go to 'Images -> Titles' and 'Images -> Captions' from the drop-down menu at the top to populate the image titles and captions with preset data (such as the image filenames).

For reference, a list of all Caption Options can be found here.
Just for the record, you could also use HTML formatting for image titles and captions:
How do I add HTML formatting to image captions and titles?

If you like, you can post ideas for future versions in the Feature Requests forum thread.
This keeps all the ideas together and ensures that they are not overlooked by the developers.
I do not know the likelihood of any suggestions being implemented but this is certainly the best place for all ideas.
Thank you.

Edit:

It looks like you've figured out what you were looking to do as I was typing.
That's good to hear! Thank you for letting me know.

That's great! Thank you for letting me know.

Thanks. You, too!

Please note that the 'JuiceboxBuilder-Lite.air' installation file installs just JuiceboxBuilder-Lite, not the Juicebox Lightroom plugin.
You'll need to install the Juicebox Lightroom Plugin separately by following the instructions on the plugin's support page here.

When you extract the 'juicebox_lite_1.5.0.zip' file, you'll find the Juicebox Lightroom Plugin in this location:
juicebox_lite_1.5.0/adobe-lightroom-plugin/juicebox_lite.lrwebengine
Just double-click the 'juicebox_lite.lrwebengine' package (Mac) or drag and drop the complete 'juicebox_lite.lrwebengine' folder onto your Lightroom desktop shortcut (PC). If necessary, manual installation instructions can be found on the plugin's support page (link above).

Once you've installed the latest version of the Juicebox Lightroom Plugin (from the Juicebox-Lite v1.5.0 zip package), the Site Info section should read "Juicebox-Lite Lightroom Plugin v1.5.0".

I think this is likely to be due to the fact that when a gallery is expanded in the same page on an Android device, the Fullscreen API is used and when you tap the device return button (after expanding the gallery from the Splash Page) the gallery exits fullscreen mode (rather than just going back one page in the browser's history). A subsequent click on the device return button will then return to the last page visited (which was the thumbnail page).

This seems to be unique to Android devices and I think it might be difficult to change this behavior. We certainly have control over what happens when navigating throughout a Showkase site using the web page navigation and gallery buttons but we have much less control over what happens when you tap a browser or device specific button.

Try forcing your gallery to always expand in a new page by setting expandInNewPage="TRUE" (in the 'General' section) and you might find that the device return button functionality is more intuitive.

Unfortunately, there's no easy way to achieve this.

As you are aware, captionPosition is supported only by Large Screen Mode (noted in the description on the Config Options page).
In Small Screen Mode, captionPosition is always set to OVERLAY, the intention being to give captions as much space as possible on small screen devices.

Juicebox was not designed with this in mind and it would probably be very difficult to try to achieve it manually.
You might need to use the Juicebox-Pro API to run some custom JavaScript code each time a new image is displayed (using the onImageChange() method). The custom JavaScript code might check the current width of the image being displayed and then use CSS to set the width of the caption area (using Juicebox internal classes and ids).
Even having done this, you'd then need to ensure that this procedure is also carried out if the browser window is resized or the mobile device's orientation is changed.
Also, being that Juicebox would not be aware of such a modification, it might interfere with Juicebox's own caption transitions and it end up not looking very clean or smooth.

It's really not feasible and is fraught with potential pitfalls. The best I can suggest is that you post your idea in the Feature Requests forum thread. I do not know the likelihood of suggestions being implemented but that is certainly the best place for all ideas as they will not be overlooked by the developers there.

Incidentally, a gallery's width and height can be specified as percentages (rather than fixed pixel values).
If doing so, you'll need to make sure that the gallery's parent containers all have dimensions set via CSS so that Juicebox knows what actual size the gallery should be (what the gallery's dimensions should be percentages of).

The only way to have captionPosition="OVERLAY_IMAGE" is to use Large Screen Mode.
You might like to try setting screenMode="LARGE" (in JuiceboxBuilder-Pro's 'Customize -> General' section) to always have your gallery displayed in Large Screen Mode. I can't be sure but this might be a suitable compromise for your gallery as it seems to be more like a banner/header than a 'regular' gallery with thumbnails.

You're welcome!
I'm glad that everything has worked out in the end.

It certainly sounds like there may be a problem with the formatting of the 'pswd.php' file.
It might be best if I could take a look at the file you are using to see if I can see any problems with it.
Please check your email. I have sent you a message. Thank you.

All galleries use a 'jbcore' folder (the 'juicebox.js' JavaScript file will be loaded into every web page than contains a Juicebox gallery). However, it is possible that not all Juicebox galleries will have their own 'jbcore' folder.
Galleries that are on the same web page will share a single 'jbcore' folder and gallery that are not on the same web page can share a single 'jbcore' folder. (Please see the Using an External jbcore Folder support section for details.)

Every gallery created by JuiceboxBuilder-Pro will have its own 'jbcore' folder but I do not know how you embed your galleries into your web pages and if any of your galleries share a 'jbcore' folder.

All galleries that share a 'jbcore' folder will also share a password (in the 'jbcore/pswd.php' file).

When you edit the 'jbcore/pswd.php' file to change the password, be sure to use a plain text editor such as Notepad++ (not a word processor or rich text editor which can introduce hidden formatting and break the PHP code) and add your chosen password (or passwords) in the $passwords array. Also, make sure that you use regular double-quotes around each password (rather than other characters such as angled quotes or backticks).

You should be able to tell where the 'jbcore' folder for a particular gallery is located on your server by checking the source of the gallery's web page in your browser and looking for the <script> tag that points towards the 'juicebox.s' file.

If you're having trouble with a particular gallery, please post back with a link to it so that I can take a look for myself and hopefully help further.

Unfortunately not. There is no way to automatically have Juicebox-Pro use IPTC metadata for image title or captions as soon as the application has loaded.
You would always need to select 'Images -> Titles -> Use IPTC Title' (or 'Images -> Captions -> Use IPTC Caption') from the drop down menu at the top.

If you were to edit a gallery (via the 'Open Gallery...' button on JuiceboxBuilder-Pro's 'Start' tab) and the source images are still in their original '/export/galleryname1' folder from when the gallery was first created, then JuiceboxBuilder-Pro will reuse the source images (with the embedded metadata) instead of using the gallery images (without the metadata). (This is what the sourcePath entries in a gallery's XML configuration file are for.)
As long as the source images are still in their original folder, you could edit a gallery and quickly select 'Use IPTC Title' or ('Use IPTC Caption') before resaving the gallery on the 'Publish' tab.
I'm not sure if this will be helpful to you or not but I thought I should mention it.

That is correct. Images that are processed for a gallery by JuiceboxBuilder-Pro (either for resizing or watermarking) do not contain any metadata. The only way to avoid this would be to deselect the 'Resize Images' and 'Use Watermark' checkboxes. In doing so, JuiceboxBuilder-Pro will copy the source images across to the output 'images' folder without processing them (with their metadata intact).

Please see my note above regarding the sourcePath entries (and editing a gallery with JuiceboxBuilder-Pro reusing original source images containing metadata). Leaving your source images in their original locations means that they can be reused (and their metadata can be extracted) when a gallery is edited.

You can. You can Shift-Click and/or Ctrl+Click images on JuicboxBuilder-Pro's 'Images' tab and then go to 'Images -> Delete' from the drop down menu at the top (or press Ctrl+D). If you find that you can't do this, make sure that you are using the latest version of JuiceboxBuilder-Pro (v1.5.0). If necessary, instructions for upgrading Juicebox can be found here.

Thank you for posting your suggestions in the Feature Requests thread.
I do not know the likelihood of any suggestions being implemented but this is certainly the best place to post your ideas.

Edit:
Please also see my reply to your post in the Feature Requests thread here.

You're welcome!
We're glad you like Juicebox-Pro and are getting on well with JuiceboxBuilder!

I notice that you have two Juicebox galleries embedded in your web page.
When embedding multiple Juicebox galleries, the 'juicebox.js' file should be loaded only once per page rather than once per gallery (and your page currently loads the 'juicebox.js' file twice).

Try removing the following line of code from your page (and clear your browser's cache before reloading your web page) to see if this helps:

<script src="img/fishkill/jbcore/juicebox.js"></script>