On 2. You're using the original fanfic definition of Mary Sue.

Rey is the original main character of her own movies and often called one. I have seen Buffy called one. The term has become misused to refer to any female character who's hypercompetent while male hypercompetent characters get a pass.

And Al does care about Sam...did I say something that implies he doesn't? He doesn't always act like he does, though.