Help with External Profile Binding

I am using EPB to send over some user information. Where can I find more information on the complete dictionary of profile...i.e., by example I know it takes name, id, and role, what about email address? Does case matter calling it "Email" or "email"?

I have sub-domains under the registered domain, for example, test.mysite.com, staging.mysite.com...when I construct the user id, should I use the full domain or just a simple mysite.com is good? It's often the case that for a production site you will have dev and stage to pair it up, but they share the same user database.

Thanks.