Deacon and Kelly arrive at the open house and are surprised that it is next door to the Heffernans. They know Doug's address and the address of the open house and yet didn't figure that out until arrival.
After Doug and Carrie confront Deacon and Kelly, they leave their apartment. The shadow of the boom mike can be seen pulling back across the wall on the left side of the screen as Doug and Carrie walk towards the camera.
When Doug and Carrie meet the new neighbors, they start seeing all the kids walking by. The neighbor says they have 8 kids, with some still inside the house. But you can count that all 8 kids are outside.