You make good sense, but for a false flag to be effective, wouldn’t there have to be some mainstream media discussion of the event? To this day, I’ve never heard that they even acknowledged that it occurred. All discussion emanated from the Q post and then took place here or on Twitter by those who follow Q.
I also saw in one of foldspace’s panels (#8) a couple of hundred posts back that the derps have their own army, navy, etc. They likely recruited those people to man the sub and carry out the launch.
Assuming that was a rogue missile shot that night, presumably it fell into the ocean without consequence. Had it hit AF1 I think there would be massive world wide media coverage. Then, for example, had the missile been fired from a Venezuelan submarine, there would be good reason to create a False Flag: a rogue US operation.