I have many clients with children who live abroad. This makes things complicated when they want to have their child who lives in England or the United States act as the executor of their estate, because the courts in Ontario have broad powers to require what is called a bond. Basically, the courts can say that the executor has to pay into court an amount equal to the value of the estate; executors can get around this by buying a bond, or a type of insurance policy, to cover the amount. The cost of the bond is not reimbursed when the money is released from the estate to the beneficiaries, so it is a loss to the estate.
Generally, the court will not require a bond if the executor is in Ontario, other parts of Canada, or even a commonwealth country such as England or Australia. Generally, the court will require a bond if the executor is anywhere else.
If you are thinking of naming a foreign executor, in addition to the difficulty of acting from afar, keep bonding in mind.