When you district account is cancelled, you will still have access to your account and log in as you have been except you will be on the free version unless you pay to upgrade your account to a Plus account.
Any shared assignments, data from school owned rosters or the school owned rosters will not be accessible after the account is closed. You can clone any shared assignments if you want to keep them. You will want to download any reports with the data from any assignments that you will need as that data will not be available after the account is closed if it is associated to any school owned rosters.
You will still have the new classes in your account after you are removed from the district account.
Please let me know if you have any other questions.