When the son is coloring, he puts down the blue pencil and picks up the red. In the next shot, he is holding blue again.
Around 23 minutes in, Regina comes down the stairs and sees that her dad has found a secret room under the stairs. Her dad comes out holding a picture, apparently very interested, and Regina asks him "What's that?" Then comes a still frame where Regina's dad is just barely visible still in the space looking at the picture although he had just stepped out of that area.
When Paul lines up his colored pencils, a crew member's hand can be seen with an air nozzle ready to make the pencil roll under the bed.