You guys make this way too difficult.
First, remember this is just security theater, just like at the airport. Cyber-thieves aren’t likely to hack into your account through the log-in page; it’s too much trouble for too little reward. They are going to go in some other way. The reason these things exist is that the people who run the sites have to have something in place to address all the people who want to complain on how lax their security is.
So, don’t worry about having answers that are difficult to guess or be able to find out. Unless you are a VIP, nobody cares. Keep it simple.
I use all lower case (I’m not sure it matters, but I do it that way, anyway). I answer the question as simply as I can. If I was Dangerosa and the question was what city were you born, it would be st. paul, not saint paul, and not st paul. All lower case, and st. paul is how it appears on maps and just about everywhere else you see it in print. Don’t include the state (the question was city). When you choose an answer, don’t go looking for ways to get it wrong, look for ways to get it right, first time, every time.
If your first car was a VW Bug, for the model of your first car use beetle. All lower case. VW is the make, not the model. Bug is a nickname for the model, the model name is beetle. Simple.
I’ve noticed that some financial institutions have started asking me questions, based on their records for me. For example, they will ask me to choose a former make and model of a car I owned at one time. Their list will include 6 or 7 popular cars with a “none of the above” choice. Perhaps former house numbers, or street names. After two or three of these (particularly if they are answered quickly) they can be pretty sure I’m me. Perhaps it gives me a little more confidence, but I suspect I am more at risk of losing my money by hidden fees, them signing me up for fictional accounts, being hacked from the inside by Russians, or a dozen other ways than someone hacking my login.
I used to agonize over the issues brought up by many in this thread, until I decided it was just for show, anyway, and to just keep is simple. You can make them complex, but simple is easier. And, yes, if you like pepperoni pizza, then pepperoni is a fine answer to your favorite pizza topping.