How to trigger action within a custom component from outside of it?

I think the model subscription (mentioned here) will help with this component being triggered when a value changes. However, it still might not some the Audio context issue of being suspended until user interaction.
One solution to this is using the video player with your audio URL. We recently added the .play() and .pause() functions (among many others), which allows for this to be triggered from another query. You can hide the controls to this which makes the component hidden.