The smartest protocol for anybody facing this situation in the future is as follows:
1. Respond to the very first threat of blackmail by explaining that Post #7 is exactly what you're going to post publicly if he contacts you again and/or contacts your school.
2. Block every means by which he contacts you.
3. If he finds another way to reach you and/or if you discover that he's contacted your school or publicized your name, post all his info right here as in Post #7.
While it would obviously be more beneficial to others for you to post his info here right off the bat, I understand that your first priority is to protect yourself; so retain whatever leverage you have by giving him a chance to leave you alone, first, instead of posting his info here right away, because once you do that, he has no further incentive to back off, but the additional incentive of pursuing revenge for your posting his info here.