Hilary, I hope you do understand truly how much effort Gary has put into all this. I provided the mechanism but he has ploughed through your difficulties turning an acorn into a full oak tree.

I have looked at jPlayer and it is a fine product. It requires jQuery v2.0 or above and Xara still only offers v1.11.1!
I can explain how to load a fresher jquery.js library.

The simplest block for mp3 downloads is to add controlsList="nodownload" to the audio Tag:
 <audio src="http://jonphilibert.com/jp/audio/load.mp3" controlsList="nodownload" controls="" autoplay=""></audio>

You can still "download" anything that is being played and I am sure that jPlayer has an similar option in its playlistOptions.
Regardless, if I can find index_htm_files/BackInWaycrossBandPitch.mp3, I can download it.
You would be safer to only offer up extracts if you wish to preserve sales. The analogy is any image you publish, someone can steal.

You need to to be explicit that the songs are copyright and that they are only available for personal listening though Jon's largesse and not for copying, downloading for saving on any other platform or media.
You should offer a link to a purchase route.

Gary offered up a vertical list but you can add the links to anything.
I would consider a useful small graphic (https://pixabay.com/vectors/search/music/) and have a rollover of the track's title.
Easy to add 40+ graphics in a smaller area.

Sorry to be harsh but you must consider your client's livelihood as prime.

Acorn