DevitaN, you could be just fine with a 690 - there's not a huge difference between 690 and 700, right?
It partly depends on the quant/verbal breakdown, and it LOTLY depends (not a word, yes we know!) on the essays. But the 690 is most definitely within range for any of those three schools, particularly for the earlier rounds. (You should have no problem with Cornell at that level - with good essays of course - they are much more flexible than the other two schools and are willing to consider a wider range of profiles.)
If you want to post more specifics then we can dig further - but you should be fine, if all the other pieces are lined up!
EssaySnark