I think you missed option 4:
NSA has the ability to intercept transmissions from multiple devices and then forward the signal to have them appear to transmit at the exact same time.
This would only require that every outgoing signal from the select devices have a unique identifier which is automatically routed through a specific server under NSA control. It is not unlikely that certain high level officials have such an identifier on their devices. Nor is it unlikely that all communications have the ability to be intercepted prior to being forwarded.
I have little doubt that the TS tech out there is about 20-30 years from the current mass market civilian tech on the market.
Just a thought.
Considered that.
But if that’s true, the question remains.
How come Q cant get THAT close to POTUS Tweets?
Which brings us back to option 1.