At the present time , subject to change, the cadet program is for emirati nationals only. other than that's an individual would have to meet the minimum entry requirements and pass the selection.
Are you totally sure about that? I myself met a young English bloke at Oxford among the Emiratis wearing an Emirates lanyard when I went for an assessment 2 years ago. He stood out from the other Emirates trainees (for obvious reasons) so I had a chat with him to see how he was training on the Emirates programme. It turned out his father was a captain in the airline and was very senior so managed to negotiate it. Emirates agreed that if he paid for his own training and supported himself throughout, they would allow him to join the other funded cadets. There was to be a bond for the 777 rating at the end.