Thanks! Great to hear you enjoyed Adam's workshop tour!
Indeed, the additional content in Audition and Soundbooth has suffered from shifting tides in technology. Audition itself, when it shipped on shiny disks, came with Loopology, an amazing collection of instrument loops and music beds recorded by Adobe Evangelist and long-haired musician, Jason Levine. Later, when Soundbooth was the audio application in the Creative Suite, an in-app panel called Resource Central provided access to our collection of around 12,000+ sound effects and Soundbooth Scores - dynamic music projects which could intelligently recompose themselves based on duration and parameters, and offered some limited mixing options.
Around the time Soundbooth was discontinued, the Resource Central servers were as well as it was based upon Flash and some legacy server backends that were being retired. To ensure users still had access to all this royalty-free content, it was moved to a download page on adobe.com and linked to in the application menu.
I have been in the process of creating a much nicer landing page for accessing this content, as well as fixing a few issues with the Soundbooth Scores bundles. Expect some news about this very soon.
Edit: Oh! As for your question about Scores in Audition, the Score projects themselves were a proprietary SBST file, which contained the sequence details for the composition, and an Assets folder, which contains the loops and clips used to make up the overall song. While Audition doesn't currently support SBSTs or Scores in general, you could conceivably re-arrange the assets to build compositions. SBSTs ARE supported in Premiere Elements since 2013, I believe.
Have a great day!