Find out...who is the 'operator' of the aircraft. That means for a part 91, either there is a very well established and clearly legally defined management contract in place with an operator, or the owner will be considered as being the operator. Then ask yourself where is the operator based? That means from where is operational control being exercised?. This can be a difficult question for a non expert to answer, and isn't just where does the person live or where is the office of the company.
You need to understand this, because of the operator is considered by the EU to be based in the EU then you need an EASA licence, regardless of anything else.