You probably already saw that link but all information are here:
D-U-N-S® Number - Support - Apple Developer
The cost to find/get a DUNS number is free of charge. Don’t use other websites which want to give for your in 24h for X euros.
It’s super easy and quick procedure (I never did with Cyprus but it should not be different).
For the office address, I am interested about this point.
Where is written the headquarter address of the company, what paper is proving that?
In CY, you can have shareholder address abroad in statuts of association and director office (even same person) in registered office yes.
The last one is headquarter, recognized officially by EMI..?