Pretty clear to me the blanks mean "objects you can't see". i.e. 18, 58 people murdered.
But everything with Q has at least two meanings. There's more.
Coincidently (chuckle), when there's a blank after the work FREEDOM in the flag posts, or an underscore at the end, maybe it means "that's the end of the show", that there's nothing left to do. Hence Q and POTUS won't stop until we are free and there's nothing left to do.