I haven't been following this nearly as close as I should have been, but _wb_ I
really like your
most recent proposed layout. There is strong parity with standard keyboard layouts, similar key press orders for commonly used punctuation, and generally uncluttered key tops. My only real misgiving is the = key, which I feel might be better suited to Meta+'/" instead of Meta+C, since it's behind a Meta key press anyway.
I'm not sure that the backlight requires a dedicated key; to me that seems like it would be accessed using a Fn/Hardware/Wonky combination, but it's not bad.
As for the current "wonky" icon, the wonkified "QFN" style chip may be more modern, but it also looks like a fabric patch. Perhaps a DIP chip or wrench icon would be more logical, and then just call it the "Hardware" key. Wonky is cute, but feels unnecessary. Maybe the
Open Source Hardware logo would be good for that, IF and only if the OSHW logo could be applied to the Pyra as it is being designed. (Did the Pandora have the OSHW logo on the label? I feel like it did...)
Edit: Forgot to mention, a hardware mute toggle would be very nice to have.