Face recognition via facebook API

You can use https://github.com/samj1912/fbrecog. Python wrapper for Facebook face recognition. And the only one in my knowledge that currently works.

Yes. You can use Facematch, an unofficial wrapper for the Facebook face recognition feature.

When you upload a picture on Facebook, the /photos/tagging/recognition endpoint is called. This program uploads a private picture (using Facebook API) + calls the recognition endpoint (by simulating a browser using the user's information).