Batch create and Batch update functions could be used to keep multiple businesses in sync.
This won’t scale. The idea is that in future, anybody can work on localizations. There doesn’t have to be established trust. This is why localizations are now developed locally and then submitted as a pull request to Github. Pull request gets reviewed and if approved then merged. This means changes have chance to be discussed, double-checked etc.
Imagine you are using Italian country-specific reports (once available) and someone comes along and will break them thus breaking reporting in your businesses. That would be unacceptable.
You can. It’s not documented feature but when you do Batch Create and your record contains Key column, Manager will use the key from batch create spreadsheet instead of generating new one.
This way you can create entries with the same GUID across multiple businesses.
Try to do Batch Create in new business and as a source of data use Batch Update output from another business.
One thing that it seems to be missing from the previous Export and Import is the possibility to create also the elements of the CoA with a shared GUID since you cannot batch create the CoA.
Currently this is not possible other than through API.
Why is it important for you to keep GUID the same across businesses again? There are going to be improvements to batch update where you will be able to use object names rather than their GUIDs. This will eliminate need to even care about internal GUID.