One poor answer in an interview probably isn't going to determine if he's hired or not, but instead the overall package is what makes an applicant.

That said, there are certainly better answers than "report him to the CP" and "want to go have a beer?". (Although I like beer... the next question I would ask is "what kind of beer?" Better answer it correctly too!)

With regards to the questions- as an FO, your best bet would be to ask the captain about his procedure out of the cockpit or once you land. Bring it up in a non-confrontational way. Such as "hey I was wondering why you do such and such" A lot of time, there is a lot of leeway in the SOP to allow for each CA's personal preferences and modes of operation. If that doesn't work, you can never go wrong by saying that you'd politely point out the way the book says to do it (in a non-confrontational way).

If that doesn't work, the next step I'd take is to approach the union professional standards committee and ask if they would talk to the CA on my behalf. There are plenty of other ways to get the point across before you go to management and create a potentially uncomfortable situation (particularly when you get paired up with the same captain again down the road).