Initial start up of food freezer
That would be a good idea since you want to be sure it works properly before putting a lot of food in it.
Water bottles should be a good volume, but I would not go by ice alone to judge the temperature since it is not accurate. Use a fridge thermometer to check for appropriate temperature.
And I would do this for a few days just in case some mechanical problem occurs. A freezer alarm would be a good idea too.