Wow!! That's a tall order of requirements 
...
You can trigger xml msgs from ECC EHP 6 and above. It works perfectly, but the issue is that in case you need to do any mapping changes, it becomes a challenge, doing it in the FM that handles your output msg. based on some logic, you do mapping changes in the FM itself and then publish the msg as an xml msg. Possible, but a unwanted pain.
On the other hand, in case your setup does not have an XI / PI box, you might still prefer it.