I am in a cross cultural, multilingual setting. I would like to measure happiness / frustration of children before and after changing rules about food and water before surgical operations are performed. What suggestions would you have for measuring happiness in both verbal and non-verbal children (verbal children may not speak English)? I would prefer a type of visual analog scale to be answered by the child if able and the parent.
Try the World Database of Happiness, if you haven't already.
There is a collection of validated 'happiness' measures here.