Should I use AP scores to exempt classes when trying to transfer?
You should maximize learning and not grades.  If you already took an AP course and actually learned the content, don't take a course that is the same as the AP course unless you are required to do so.
Repeating courses for an 'easy A' will waste lots of your time and potentially your money too.  And there's no guarantee the course won't turn out to be much harder than you expect.