With funeral insurance you pay a regular premium to cover the amount that you think will cover the cost of the funeral. This is usually paid as a lump sum to your loved ones on your death.
A funeral plan allows you to pay for your funeral in advance, fixing the cost of your funeral at today’s prices. You also can predetermine the specific items you want on your funeral. Well established funeral directors also can offer payments of the agreed costs by instalments.
In conclusion, you can insure your lump sum for the funeral but have no control as to how the money is used or you can have full control and plan your whole funeral in advance.
I find it quite staggering the number of funeral directors offering their services to foreign residents on the Costa del Sol, especially to English residents. Which means that there is money to be made in a nondying business to a consumer that cannot complain for the service received.
Common sense dictates that your best bet to rest in peace is to do as the Romans do and consult a long established, reputable, professional Spanish funeral director, who knows exactly what to do to fulfil your wishes. These days they can also do it in your own language.