Can you help me understand some things about To Kill a Mockingbird?

Note: Spoiler Alert! I know this is an old movie, but if you haven’t seen it and don’t want to know the plot, do not continue with this question.

Until two days ago, I had never seen the movie To Kill a Mockingbird (I have also never read the book). I have been trying to watch more classic movies and this is one they actually have on Netflix.

Anyway, I enjoyed the movie, but I had a question about the little boy named Dill. I couldn’t figure out why this character was even in the movie. Then I decided to look online in the Cliff’s Notes (or equivalent) and Wikipedia. I found out that the book is extremely different from the movie. In fact, there are lots of characters that don’t even get mentioned in the movie, and others that are conglomerations of several characters from the book that get rolled into one in the movie.

I understand that because a movie has a limited amount of time, you can’t always present everything and everyone the same way in the movie version, as in the book version. But with this movie, it seems like it is a completely different story, with different characters. Here is a Diagram of some of the differences.

It just seems like there is such a huge difference between the story line and characters in the book, than there are in the movie, that they are almost two different things, rather than slightly different interpretations of the same thing.

I had always heard that both the movie and the book were these big important, milestones in literature and film making, and that may be true, but they seem like apples and oranges.

I still don’t get why the character of Dill was even in the movie. He seemed to serve no purpose. Apparently in the book, his character was much bigger and he was supposed to be a metaphor for something, and a contrast to something. In the movie, he’s just a cute kid who lives next door.

Would any of you literary types like to explain Dill to me?

Also, did Atticus actually think for a moment that his son Jem killed Mr. Ewell?

How did Boo Radley get Jem back into the house without Atticus or Calpurnia seeing him? Didn’t anyone notice that he, Boo, was standing behind the door until Scout pointed out that he was right there?

Did Boo Radley actually stab his father with a pair of scissors? I’m guessing that he did, but not because he was a bad guy, but because his father was a bad, abusive person.

How funny is it that Scout is dressed up like a piece of ham? Is there a significance to that? That seemed like a scene right out of Leave It to Beaver.

Anyway, any discussions on To Kill a Mockingbird are welcome.