iCloud question with multiple ME e-mail addresses

Greetings,

We are a family of 4. My wife and I use our domain e-mail addresses tied to 1 Apple ID for Apps, mac Appstore, contacts etc. My kids use the same Apple ID but no contacts etc. We separate our contacts on our devices using Groups.

I'm wanting to start adding a few other Apple addresses under the Me.com domain to utilize some of the other services like notes, mail, etc. Today I setup a new Me e-mail and it just added it under our main Apple ID email address with no password. If I want to setup more, how does this all work under the Apple "Eco system"? Is it time to start migrating all this stuff apart or will it all "just work"? Will they all have the same password under iCloud?

//Cheers