yes, it could also be she is not a monkey
Can this not be "he is not a monkey" as well?
I think so. If the monkey were your pet, for example, you'd probably not refer to it as "it".
Specifically, when do I use "NO" and when do I use "NON"?
No is the word for no, non is part of the phrase using the negative form of the verb. So closer to 'not'
No that is obviously the zookeeper, Jimmy Jr
How could you mistake someone for a monkey!!??
It would not be uncommon to compare a climbing child to being (agile) like a monkey.
One might then say in reply 'no, she is not a monkey'
If the someone was the Librarian, it would be the last thing you did.
You can say so because 'it' is reading a book.
Oh, look at that monkey in the cage!
No it is not a monkey