Did you have a Family Pack or did you have aliases - the latter are additional addresses, not accounts, which deliver into the same inbox as the primary address; Family Pack sub-accounts have their on login and are separate.
Aliases should have carried over when you migrated and be configurable at http://icloud.com in the Mail page - click on the cogwheel icon at top right, choose Preferences, then Accounts.
Family Pack sub-accounts should have been migrated individually and would have become full separate iCloud accounts. If you did not migrate them they have been closed and their contents deleted. You can reactivate the address for an ex-sub account by signing into System Preferences>iCloud with it, but you cannot retrieve the previous contents. In any case where you want the address to be deleted you need do nothing - it already has been.