This is a question of 2 different possible statuses, each with its own implications.
In Maurice Lamm's "The Jewish Way in Death and Mourning," he writes (page 26)
He is not considered an onen if there is absolutely no possibility of his participation in the arrangements
Thus, he or she is not an onen if ...
He could not physically be present at the funeral preparations because he is...overseas
I understand that to mean that if someone is so far removed that he or she could not be at all involved, then that person is not an onen. But if that person WILL be involved at a later date (as the body is being transported to the overseas location) that person will BECOME involved and will then be an onen, and then an aveil.
So what is the status of the person before he or she becomes an onen?
And if there is a delay in the moving of the body, if the person overseas is an onen, for how long can a person remain an onen?