Hey! Don't stress about the tests! As I've said in other posts, I got into NU with a 1220 SAT and nothing higher than a 3 on every AP. I also didn't break 600 on any SAT 2's. But I did maintain the 4.0 and take APs (just like ur doing) lol...some of us are horrible test-takers! NU understands that, if you redeem urself in other areas. You have time to bump these scores up up! And yes, they will look at the highest of all of your test scores. Your GPA is great...and as long as u have great extracurrics, recs, and can write solid essays...u shouldn't have a problem. Bleed purple (especially for ED)...that's all Northwestern can ask for
P.S. I dont think u get to choose which AP scores are sent. Im pretty sure all of them r listed on one document.