The pace of the text quickens to move the story to its climax, the completion of the windmill.
The pace speeds up here. Starting "By the autumn" shows that the narrator has skipped the daily, weekly or even monthly events until autumn arrives. We know the goal of this skipping is to be able to get to the part about the windmill since it is the last detail mentioned. Also, it says that "the windmill compensate for everything" showing that it is important to the animals. There are no flashbacks or examples of foreshadowing in these passages.
The answer to whether or not you can use two negative words is true i believe.
