SychO I think you're right. I had considered continuing with Toby's original idea, but it sounds overly complicated. He talked about overlaying shortcuts on the UI elements by pressing a key. While it sounds cool, it would be hard to manage on some elements.
It would be simpler to place a button somewhere with a keyboard icon that opens a modal with all available shortcuts. This way, you wouldn't have to navigate to the specific UI element to learn its shortcut.