Yes, I know. I try to avoid fair use, or at least tread very carefully assessing the risks. Yesterday I published a piece about a Christmas song causing outrage. I shared some lines from the song. It was made up by a church member and has been widely reported in the news, which is where I got those lines from. I think it's fair use. But if those lines were owned by a record company rather than an eccentric church member, I probably wouldn't have written the story. Because depending on who you're dealing with, the risk of legal action goes right up.

I don't know more about defamation and don't really understand your question. Not an expert sadly, just reporting on what I find.