This app was mentioned in 6 comments, with an average of 2.17 upvotes
I'm pretty sure an app like this was featured on All About Android the podcast. I'll get back to you with the name
Edit: https://play.google.com/store/apps/details?id=com.ssrij.fingerprintunlockmac
Looks like it does everything you want.
DroidId to unlock your mac with your fingerprint.
https://play.google.com/store/apps/details?id=com.ssrij.fingerprintunlockmac
Droid ID does the same thing for Macs.