Re: Fatal Flaw?
I think there's an interesting discussion to be had about split protagonists, but I have no idea why CASABLANCA came into it, because by no measure is Laszlo a protagonist.
CITIZEN KANE would be a much more interesting film to analyze in regards to this. You have the reporter and his conflict about discovering the nature of Kane's last words, and then you have Kane himself. The reporter acts as a surrogate protagonist for the sake of moving the plot forward.
A narrator character like Red in THE SHAWSHANK REDEMPTION fills a similar role. It's not their conflict. It's not even fully from their perspective, but occasionally they take on that burden, and they usually have their own conflict to overcome as a subplot that further informs the theme of the film.
I don't know if there's an official term for these kinds of characters. Shame on me for not reading the thread closely if someone knows and provided that answer. I've referred to them as "access" characters in the past.