What is the author’s preferred writing style in The Chrysalids? What are the narration and use of dialogue like? Does he favor literal or...

There are quite a few questions being asked in your post.  I will answer the question about Wyndham's preferred writing style.  My answer will touch upon the other questions being asked.  

Generally, there are four recognized types of writing styles.  They are expository, descriptive, persuasive, and narrative.  Wyndham makes the most use of the narrative writing style.  That shouldn't be much of a surprise, because it is the narrative style that most authors use...

There are quite a few questions being asked in your post.  I will answer the question about Wyndham's preferred writing style.  My answer will touch upon the other questions being asked.  

Generally, there are four recognized types of writing styles.  They are expository, descriptive, persuasive, and narrative.  Wyndham makes the most use of the narrative writing style.  That shouldn't be much of a surprise, because it is the narrative style that most authors use for novels.  

A key feature of the narrative writing style is that a person tells the story.  In The Chrysalids the story is told by David Strorm, and the story is told from the first person perspective.  The narrative writing style also makes use of multiple characters and dialogue between those characters.  Again, that is very true of The Chrysalids.  The character list is quite large, and the reader learns a lot about character's actions and decisions through the dialogue sequences.  For example:  

'Go on,' I told her impatiently.

She tried to move, and then called up,

'I can't. It hurts.'

I risked pushing off, anyway, and landed close beside her.

'What's the matter?' I asked.

Her face was screwed up. Tears stood in her eyes.

'My foot's stuck,' she said.

Much of the narration in the novel is similar to the above sequence.  Wyndham's narrative stays quite clipped and concrete throughout the novel.  There isn't much flowery, figurative language that is used.  Perhaps that is because the narrator is young and doesn't think like that yet.  Or perhaps it is because Wyndham knows that his audience is likely adolescents who want to read about actions more than they want to read about metaphors.