Jonathan says that Max will be home soon to rescue them. Immediately after that he's in the backyard playing ball with Freeway.
As Jennifer, stefanie powers usually has very short nails. The finger that presses the previously unknown button behind the clock, the nail is considerably longer.
It would be physically impossible for old Max to pull Mr. Hart up out of the well with that hand crank, with that lack of leverage, it would take at least 4 big men to get enough force.
The fire in the camera box goes out immediately, leaving just some fake smoke, even though old nitrate film is highly flammable.
GOOFADDITION
When Jonathan begins calling to Max, Jonathan's voice can be heard near the top of the structure, rather than at the bottom of a deep well.
In all the years that the Harts have lived in that house, and before that Jonathan and Max, it's odd that no one has moved that clock to dust under it, and notice the button on the wall.