To be an AP scholar, I believe you need to average 3 or higher on at least 3 full year subjects. To be an AP National Scholar requires an average of 4 or better on a certain number of exams. I'm not sure how many. Sorry I don't have more info, but high school counselors should know this stuff. Sadly, many of them don't.
Many schools are discounting exams and grades and looking at community service, etc.
Sorry I don't have more info. When I was in school I wasn't involved in any scholar programs.