Wuthering Heights

With this particular story I am torn between the two options; are the characters free to do what they want or are they governed by something bigger. I am stuck between these two options because of the evidence on both sides. First let us discuss the freedom of the characters to chose.  In the story each character can chose how and what they react to. For example it was Isabella's choice to love Heathcliff, as it was with Catherine. Heathcliff chose to never move on and becomes consumed by the misguided thought of revenge. Throughout the book the characters exercise free will making it appear that the answer to my big question is obvious. However it is the elements the characters can not control that one could argue shows fate was involved. For example, characters throughout the story would be stopped by the weather, allowing for the plot to continue. Furthermore sickness is constantly changing how the story plays out. Imagine if Lockwood never became sick and Nelly never told us her story, or if Catherine never stayed at Thrushcross Grange. The story would have been completely different. It is due to the duel nature of this story that I am at a loss for an answer. So I leave it to you to decide, do you think the characters where mere playthings for an already known story or that the story is purely do to their own actions and thoughts?