1. DRC would catch it but your bridge ground is floating.
2. If I were doing it, I'd change your RC delay by increasing R and decreasing C. Resistors stay same size and same cost irrespective of value, capacitors generally decrease in size and cost for values shown. Ceramics IMO generally more reliable than electrolytics.
3. I'd change the inverter after the RC to one of the unused HC14 gates. Don't know about cost but it might be cheaper and smaller pkg for a single NOR than a dual NOR. Also, for the RC time-constant you really should protect against possible oscillation on that inverter so the HC14 hysteresis will handle that.
4. Presumably you'll hold off ordering boards till you do more testing, but I'd give a bit more thought to how-to isolate the RF receiver. This could be a simple bead filter between power-supplies should conducted susceptibility be the issue. I also can't help think of consumer electronic devices where, when you open it, the RF module/tuner/whatever is usually in a shielded can/enclosure. In other words, different than shielding the MP3 electronics.
In any event, I am genuinely excited that you are still considering a general purpose approach rather than a TMCC-only version requiring a somewhat spendy ERR module. I understand your comment about cost, but if in the end you do need to go with a $1 microcontroller, a lot of SPI code talking to JGL's a $1 2.4GHz module I still think the cost will be reasonable. Actually my concern is that the general OGR readership "gets" the significance of what we're talking about here. I don't know what to do about that aspect though.
IMO if you can pull this off - allowing connectivity with an ASC/AIU, this will have a greater impact on the hobby than your super-chuffer and LED board combined.
