I'm an engineer, gun owner, and former NRA member[1]. I hate the idea of smart guns, but politics are a distant secondary concern. Firearms fail all the time, even the simple reliable ones. Bad primers, failure to eject, failure to cycle, stovepipes, etc. It takes education and then repeated training to know how to deal with failures. In a pressure situation you revert to your lowest level of training; muscle memory…
See, I actually like the idea of smart guns. The only thing it really does (or should do) is prevent you from getting shot with your own gun. If someone steals your gun out of your house, they could remove the smart part. If you're thinking about logging gun usage, you could probably edit the logs or corrupt them beyond usability. I think you could make the system work. It's not complicated, maybe just an RFID reader…
Don't forget the power supply, and don't undercalculate antenna design needs (it probably won't work incorporated into the handle of a pistol). The electrical draw will probably need to be pretty beefy in order to be as reliable as the rest of the gun's mechanisms, and what happens when the gun is being carried or stored in -20C temperatures? What about off-hand shooting when your normal shooting hand is unusable or it's dangerous to shoot from your normal side?
In order to be both universal and not introduce unreliability, the solenoid would likely have to be introduced as a secondary safety. How many firearm designs would even support a secondary safety?