How do you keep track of phony answers to security questions if they are different for each site? If it is the same phony answer for every site, it is not any safer to use real answers to the security questions.
Even if you're using real answers, you will be locked out of your account if you don't treat them like passwords. Eventually.
There will be no reuse, because for Facebook it would be buddyfacebook or dugfacebook, or something else… but you will always be able to guess it in three tries. A computer system doing some kind of pentest isn't going to parse out the "facebook" or "lastpass". A human might, but that's why you rotate through three names. At the point where you have a human targeting your account and actually thinking about your inputs you are probably !@#$ed anyway.
!%!%example.com%!%!
It was clear to me after I had to read such a security question answer over the phone to unlock an account the CSR was perfectly happy with "gibberish over the phone == gibberish in front of me", meaning my attempt to secure things made it less secure in the end.