Re: Multiple user types – possible?
The permissions plugin will be an integrated part of BuddyPress when version 1.1 comes around. As it stands today, it isn’t available to anyone but the developer(s). 
If I am understanding you correctly, profile groups and fields are used as pages of user editable information within their profiles, so you can have a group for “Personal” one for “Contact” one for “Pets” one for “Vehicle” etc… It’s part of the Extended Profiles plugin, and will also get a bit of a facelift for 1.1.
If you need to set permissions right now today, unfortunately I don’t have a real great answer for you yet, other than kind of side stepping what you need until a built in option comes available.
