Issues Raised by Audio Attached to a Button

My goal is to access embedded media via the interface that you can view at the Dropbox link below: just click an icon and the media opens. It works with both video and audio, but the audio (which uses a button) presents an issue that worries me: Why are buttons that play a sound limited to WAV files instead of, e.g., MP3, and what are the chances that attaching WAV files to a button is a security hole that Adobe will discover and remove later, thus wrecking my project if I depend on it? After all, if WAV files embedded via the Multimedia Sound Tool trigger the ‘Do you trust this?’ message in Acrobat Reader, why would they be allowed on a button? And if the Multimedia Sound Tool requires H264 (e.g. MP3), why is that NOT available for attaching a sound to a button?

Here's the Dropbox link: https://www.dropbox.com/s/9ghu3l5fkfj2t7i/40_2007%20Test.pdf?dl=0

In case you’re wondering why I don’t just embed the audio via Adobe’s Multimedia Sound Tool, the reasons require some detail to explain:

First, the reason for icons has mainly to do with the video clips: big posters inside the document will take up far too much screen space since there are many hundreds of them; readers (who are fellow linguists) will find it cumbersome to follow the discussion. My approach solves this by opening the videos in separate windows.

Second, now that I have adopted that solution for the videos (the orange ‘film strip’ icons), having ‘speaker’ icons for the audio provides a consistent look and feel.

Third, going with the built-in Adobe audio interface would require me to change the hundreds of little Word docs (ready to convert to PDFs) that I already have.

Fourth, simply attaching the audio to my icons via the Multimedia Sound Tool leads to an unacceptable result that you can witness by clicking the leftmost ‘speaker’ icon: the sound plays once, but then the Adobe audio interface bar appears inside my icon – far too small to be usable.

Fifth, going with legacy media as I have been doing until now  leads to the ‘Do you trust this?’ warning. That was okay when I put large collections of media files (like 40 or so at a time) inside one big PDF. The ‘Do you trust this?’ message was triggered only once for the whole PDF. But my new approach of lots of little PDFs will frustrate my users as the message is triggered again and again and again. Even worse, the legacy approach no longer works at all over the internet. (For example: all the icons on a little legacy media (WAV and MOV files) website I did long ago (www.vincentasl.info) have stopped working, apparently now blocked for security reasons; click on them now and nothing happens.

Attaching the sound to a button works great, as the second speaker icon shows: just click it as many times as you want and the sound plays. But as I said, it only works with a WAV file – and that’s despite the fact that MP3 audio (and even MP4 audio) sound files reside in the same folder as the WAV file. My big worry is that if I go with this approach, Adobe will pull the rug out from me again just as happened with the legacy media approach I was using before.

Are those problems fixed a later version of Adobe?  I have Acrobat Pro Extended version 9. Unfortunately Adobe no longer offers versions 10 and 11 for purchase, and is charging $499 for Acro Pro DC, since upgrades from version 9 are not  permitted. But I will definitely buy it if is solves my problem.

P.S. The media in the PDF at the Dropbox address plays on both PC and Mac, but only in Mac OX 10.6 or higher.