Really, above your soft factors, your numbers are the most important thing. I don't see you having a shot at BU or BC. While your GPA is surely competitive at both schools, BU and BC both have a 25th percentile LSAT that is 10 points higher than yours.
Northeastern could be possible but is probably a reach. You're still 5 points out of their LSAT range, but their 25th percentile GPA (3.19) is way lower than yours, and thus you might have a chance when your index number is calculated.