I haven't looked at your capx yet, but here are some general ideas:
A progress or percentage bar is always current amount divided by the total. So you'll need to be able to answer the two questions "How many people have water?" and "How many people need water?". One way would be to run a For Each loop, adding 1 to a variable for each object that meets the requirement "Has Water", and then divide that total by the total number of objects that should have water. Same for food.
For happiness, one way to do it would be to have a similar percentage bar, but count each category of need instead. So if you have two needs, and you only meet one of them, that object would be 1/2 happy. Your happiness amount can change over time instead of being instant if you want to make it more complex.