Does Ultimate Facebook only work with a facebook app? Can I use a facebook Page instead?

A few questions

1) On the wpmu website you can log in with either Google or Facebook. Is there a plug in available that does this? Is this the Ultimate Facebook app?

2) Can you “Log in with facebook” (or google) when purchasing a subscription from the membership plug in?

3) If you use the “Pay with Like” app and someone likes your site, does this count as a “like” towards your facebook page? Or is this different?

I am pretty unfamiliar with how Facebook likes work! Thanks for your help