Not a hacker by any stretch, but I read and follow and listen to a variety of information security related stuff from several perspectives.
Top thing: You can lie on your security questions. As long as it's a lie you'll remember, sites aren't fact checking that your childhood address wasn't 123 Sesame St.
Next thing: With things like two factor authentication (when website or service texts you a code to put in, either cause you forgot a password or are on a device/network they don't recognize), security questions are not as big a focus for folks trying to access your accounts as they were in the past. Yes, it did work, and could still in some situations, but unless a hacker is gunning for you specifically, there are more effective ways to get into multiple accounts.
Having said all that thing: I'm more concerned that the polls, sites, and accounts asking for such personal data from as many people as possible are doing so for more targeted, personalized advertising and building a better profile on the people who answer. First car was a 72 Nova? Show them more muscle car accessory ads. Mother's maid name is full of consonants? Put "travel to Eastern Europe and find your roots" ads in their feed.
So, no, you really don't need to tell FB your first pet's name, but more to work against the virtual you advertisers want to make of you than to save your bank account.