Hey Ashton,
The synths are components, not assets, so there aren’t any ways to trigger them from within SoundCues right now and frankly, I’m not completely sure how that would be accomplished or what parameter control would even look like–parameter passing in SoundCues is extremely painful and SoundCues are so obfuscated from the rest of the game logic that my hearty recommendation is to use SoundCues sparingly and only for cases when similar logic would be less convenient in Blueprints–generally speaking, Blueprints are far superior in terms of logic and generally will perform better. SoundCues are very much a legacy system and the entire SoundCue graph is evaluated every tick, which in cases of complex SoundCue graphs is actually really terrible for performance (compared to the execution oriented BPs).
As for the GUI, we’ve considered trying to include it in a Content Example some time down the line, but it was just a runtime UMG interface I made for modulating synth parameters in real time. It had limitations because the Modular Synth is modular and the UMG widget wasn’t. With that said, we are interested in exploring ways to edit preset data in the Editor and hope that we can improve interfacing with Audio assets, effects, synths, etc. overall–at the moment, Slate is something we’ll need to learn more about to achieve this, so I don’t know when we’ll be able to get to it–but we want to do it, for sure!