Other than paying for a plugin, and since you've already created each separate layer in each separate screen with no 'connection' to a smart object or each other, it's not currently possible.
My suggestion, since you would have to go through each screen separately now anyways, would be to:
- Add a smart object layer filled with color and mask it to the object you want colored(alt/option-click between the layers in question with the colored smart object on top).
- Copy(alt/option drag) that smart-object-color layer above any other objects that need that color, mask again, etc. Do this with as many different colors as you need.
- Then, if you need to change colors again in the future you can double-click one of the smart-object-color layers, fill with the new color, and all corresponding smart objects will update, changing the color wherever that smart-object-color layer has been copied.
Again, doesn't alleviate having to go through all your screens this time, but might save you some time in the future. Hope that helps.