This one is about if copyright [or any other kind of] permission is needed for quotes associated with living people, or from the 20th century, particularly if such quotes are mentioned in biographies that are still under copyright.
People sing ‘Happy Birthday’ to their friends and family all the time, and half of them sing it twice while washing their hands, but until recently if you wanted to sing it even once in a movie you had to pay royalties.
I’m wondering what about if, say, a baseball-mad MC were to say things like “As Yogi always said – you can observe a lot just by watching.” Or a protagonist who, while facing a choice, thinks of the Madeleine Albright quote, “I have had fun being who I became, so to speak.”
Is it OK for a fictional character to quote real life people? Or, if the book is published, does it then need formal permission?
Quotes like the examples you used fall under fair use, which is a slippery little thing and you need to be careful.
You can quote Martin Luther King saying "I have a dream" but you can't quote more than a few lines of the speech itself. Which is something the producers of the movie Selma found out the hard way.
You can quote lines from the blog, but you can't cut and paste an entire blog post and publish it.
Fair use means small pieces of a work, properly attributed. When you use song lyrics, or poems or large chunks of someone else's work the lawyers start sniffing around.