On a MacBook Air, running OS X El Capitan, can two different Users login to their own User Account while accessing their own individual and different iCloud Accounts?
Yes! Simply create a second user:
Add a user
- In Users & Groups preferences, click Add (+) below the list of users.
- Choose the type of user you want to create from the New Account pop-up menu.
- Type a full name for the new user. ...
- Enter a password for the user, then enter it again to verify. ...
- Click Create User.