Is there a simple way to add masked multiply and screen shading to animations? (like Photoshop)

G'day all! 
I've completed an animated symbol of an angry old man and I want to add some simple shading to him. Which is the best course of action?
1.) Draw the shade manually to each graphic symbol making up the animation (e.g his legs, arms, torso etc)?
2.) Create another layer above the animation and manually draw the shadow avoiding going outside of his outline?

3.) A magical way I can create a mask layer that only colors the artwork with different blend modes/transpareny available (like Photoshop)?

4.) Another way altogether?
Any help would be awesome!
Cheers legends!