You don’t need to be setting the implementation name. You’d only need to use that if your team had written, say, an FMOD integration and wanted to use that instead of Wwise. That said, on Lumberyard, the cvar is named s_AudioSystemImplementationName.
For debug drawing audio-related information on screen, you can use s_DrawAudioDebug. As you’ve seen, the characters you pass as options are like flags. Type s_DrawAudioDebug ? to see the help info about the command, or simply type the command without any options to see the current value.
If you want to see the red spheres and text where sounds are playing, then abcde should be fine. Another helpful flag combo that I use is vw which shows active audio objects and events in a list. If you are having any issues with banks, use x to show the currently loaded soundbanks. And finally, to turn off the display, just pass zero (0) to the command.
Hope this helps!