does every menu item in an app have an intent? In order to filter through my music better and get rid of 'stuff I know I don't want to hear again', I'm considering 'how to best go about writing a Tasker plugin' to 'delete the currently playing song'.

Detecting what's currently playing, searching for, and deleting it would be more complicated than being able to emulate the code that runs via menu item->delete->Yes dialog.
the AndroidManifest.xml inside the APK [the APK is just a compressed folder that you can open with WinRAR] contains a list of the available intents.