First, Q+ (Trump) is the military Commander in Chief, so he's probably one of the military ones.

Second, the Q team here is describing the number of people who have the "full picture." There are certainly others that would some compartmentalized knowledge of the plan. Even Dan Scavino may not be one of the 3 non-military, despite him likely being the one assisting Trump with Q post timing and content for Tweets, etc.

We know Dan Scavino, Mike Pompeo, Chuck Grassley, Trump, Don Jr, Eric Trump, John Durham, and likely Melania all have some knowledge of the plan. This is in addition to other possibilities including Michael Horowitz, Jeff Sessions, John Huber and Chris Wray (sleeper?), in addition to probably several military people in the White House Communications Agency. It's possible that all of those aren't in the <10 the Q team is talking about here.