Punctuation for imagined/interpreted content in narrative

Question

1. He had a look that said "I hate you".
2. He had a look that said 'I hate you'.
3. He had a look that said, "I hate you".
4. He had a look that said, 'I hate you'.
5. He had a look that said "I hate you."
6. He had a look that said 'I hate you.'
7. He had a look that said, "I hate you."
8. He had a look that said, 'I hate you.'

Which one/s is/are right?

I checked this Usage of imagined content in direct speech, but it was not very relevant as the content is not part of a dialogue or thought of the characters but perhaps of the narrator.