Serious Ways to get schools to give up info?

I highly doubt you'll get a actual password out of them. The response will probably be that they will email a password reset link to the parent who you claim to be. Yet you might still get the email address, by telling them you have many email addresses and you'd like to know which one the account is with. Be ready to answer some questions regarding you as "parent" (who are you to the child: Name, data of birth, workplace, etc) and have as much information about the target as possible, the one you'll be talking to could be ask questions about your "daughter". If you fail there by telling them "idk when my daughter is born" or what's the name of your wife or husband (depending on who you claim to be) you can be caught telling a lie pretty easily. Solid background story & loads of info, will definitely increase your success rate. Keep in mind they probably keep parent's phone numbers somewhere, so have a good excuse of why are you calling from strange number.

Good luck!