BU was not always selective. As recently as 2002 they admitted 70% of applicants, In 2012 they admitted 45% of applicants. They only became very selective when they cut the freshman class from 4100 to 3300 students.
At all three of these schools admission cannot really be predicted for students with high stats. Also all three have an alternative entry route: Oxford at Emory, CGS at BU and NU In at Northeastern.