1) Currently the only way to do this would be to create an alias with multiple addresses, and then use the alias as the email address for the official. However, it's also relatively easy for the official / parent to setup an inbox rule to forward certain messages to alternate addresses. Therefore most associations would hand the task of multiple notification sources back to the officials.
2) The system requires unique email addresses for each user that's in the system. This allows for self-retrieval of forgotten passwords. With the prevalence of free email services like Hotmail, Gmail, Yahoo!, etc there's little reason these days for each person to not have their own email address. And as described above, each of those services would allow for forwarding to be setup in order to deliver mail to the shared family / parental account.
3) At present they cannot. Most of the larger centres using the officials module would prefer that the workflow for updating an official's contact information starts with the assignor due to that change needing to be made in other systems (like a payroll system of some kind).
Hope that helps,