BTW it is possible to do classics ab initio, you just have an extra year on the course.
Languages, history, EngLit, would all be useful APs for Classics or Theology, if you apply next year.
As you have a number of APs in hand you may get an offer from some of the other universities on your list if you apply this year, and you should be able to defer entry if so.
St Andrews is generally understood to be the easiest for US students to get in.