[not a teacher]
I read "all Nature" as plural on its face. But in context, it most certainly is:>> first - do I understand the meaning correctly?
It’s hard to tell, because you didn’t explain what you think it means (I’ve never heard “in scorn”). My reading is that “to scorn” is the infinitive verb meaning “reject or dismiss as contemptible or unworthy”, meaning that “all of nature is laughing at him to reject him as contemptible”.
>> third - is it a construct you could call a "contemporary English one"?
“were laughing him” is not a construct I’m familiar with. Perhaps it's the same as “the parents were lulling him to sleep.”
I’m anxious to hear what others think!
Student or Learner