The GPA and MCAT gets your foot in the door, but then after that they look at the application as a whole. They dont accept anybody that they dont think can make it in the school. So if you have like, a 480 MCAT and you seem to be a decent student do well in classes, and have a very well put together application. I think that they would be more inclined to accept you into MHS to give you a chance to get the 503 needed and continue to excel in classes. Obviously, I’m not on the admissions board so dont stake too much on this, but I do know that there were plenty of past MHS people who had a lower MCAT score, and they went through MHS, got the score they needed and went on to med school.
As far as specifics that the admissions committee looks for, I do not know What things may stand out to them the most. I would just say be your authentic self and let that show through your application and eventual interview date.