the best way to answer it is to compare and contrast the way that the text introduces and describes the three ghosts. You are right in being aware of the general symbolism of each ghost and the time that they represent, but it is important to realize how each ghost operates to taunt Scrooge with the kind of man that he is now and with regret...
I think "pay attention to what helps you get through hard times" sounds relevant
number 4) A snake crawled out
crawled out is a transitive verb
