1 Account w/3 email addresses & address questions

1 Account w/3 email addresses & address questions

Hi,
I am wanting to change our personal email from Yahoo to Zoho.  I have a few questions before we make the move.  This email system would be for both me and my wife.
 
1.0  LOGIN username & password with 3 email addresses.
1.1  We would like to have one username with a password to login to Zoho Mail.
1.2  Then we would like to have 3 email addresses as follows:
        A. A personal email address for myself
        B. A personal email address for my wife
        C. A commercial email address for our commercial use
1.3   Our goal is for either one of us to login with the same username and password
        and be able to view any of the 3 separate email address inboxes, etc.... 
        We are not concerned about privacy between us.
1.4   Is the above possible with Zoho?
1.5   Are we able to have 3 email addresses in our email account?
 
2.0   Email address clarification.
2.1   Personal use of the Zoho email system is free, such as name@zoho.com
2.2   If we want to use a different address, such as name@xxxxxxx.com, is this free also?
        Of course we would not request "xxxxxxxx" as part of the email address.
 
Thanks for you help in this matter,
John