I think that with that last test score, you’ve got a good plan.
Her class rank will help her get a serious look, but I disagree that it’ll guarantee admission. I have known of many vals, including those from bigger and more rigorous high schools, who have been surprised by admissions results.
One refrain you often hear at those super-competitive high schools (test in and boarding schools) when you ask about the college applications process from such a qualified pool is "College AOs know that if you have excelled here, you’ll have no trouble at their institution. " The unspoken corollary is that there are kids who excel in high school and arrive unprepared for what faces them. With the scores you have now, I think you’ll have done good work in addressing that fear.
I would not have the GC explain why kids don’t take AP exams – lots of schools use block scheduling and make it work. But I might ask if they could say what % of the class took the tests last year (if indeed it’s so low.) There is the possibility that the explanation of why so few kids normally test could also reveal that these are AP classes in name only, which could diminish their value in the eyes of the AO.
With all that said, I think your D has as good a shot as any unhooked excellent student at the schools on her list. Hoping you’ll be sharing your good news here in December!