Heh I JUST wrote another comment saying that I wanted VOICE:) I was hoping easydiscuss was going to have a way of working like your VOICE does. Anyway...
two-factor authentication integration for your easysocial should be dead easy. I would just take a look at the new user login module with j3.2 and see how it works. Basically, if two-factor auth. is enabled, there's a third input field. so to login, you need your username, password and then another code.
Check it out on j3.2, its brilliant and super easy to use. It does require 3rd party app on your mobile device, but I found one for my BlackBerry z10. Basically what happens is you turn on two-factor auth, then in your user manager it shows you a QR code. You scan that code using whatever two-factor authorization app you have on your mobile device, and it then gives you a 6 digit code that changes every 30 seconds.
So in order to login to your site, you have to open that app and enter that code along with your username and password. So currently, if i'm using this feature, I can't use your easysocial login page until you add that additional code field.