Box 1: Yes -
Storage1: Storage File Data SMB Share Contributor is assigned to User1.
The Share1 on Storage1 is transaction optimized.
Storage File Data SMB Share Contributor, Allows for read, write, and delete access on files and directories in Azure file shares.
Box 2: Yes -
Storage2 has Share4. User2 is the owner of Storage2.
Box 3: Yes -
Reference:
https://docs.microsoft.com/en-us/azure/storage/files/storage-files-identity-ad-ds-assign-permissions