2 Sites 2 Domains Same database

I'm not sure if this is the Mapping plugin is what I am looking for or if what I am looking to do is even possible.
2 Sites - Social Network & News Site both with own domain.

Question 1: can profile and login info be shared between the two
Question 2: I would like to keep them as 2 separate domains and databases is that possible?

I really do not want to have to use subdomain to make this happen but if I must i must lol