Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
If you have a Microsoft 365 Family subscription, that comes with 1TB of OneDrive storage and the installed version of the Office apps, the Basic subscription only provides 100GB of OneDrive Storage, so if 1TB of storage is enough for your needs, you do not need the Microsoft 365 basic subscription and you can cancel that.
With regards to the Email address, provided you use the exact same Microsoft account for the Microsoft 365 Family subscription, you will still have access to all your files and data on the new subscription.