Have you considered using transparent masks? This is how I did cheap lighting in my game.
What you do is
1. Create a layer in the scene editor, call it 'lighting' above everything except the ui layer
2. Set the layer background color to some default color, like black. This represents darkness
3. Create a circular sprite, the outer edges that are 'dark', are the same color as the background color for the light layer.
The 'light' portion is a partially or fully transparent circle in the middle of the sprite
4. Assign the new sprite to your light objects
5. Spawn or place your light objects on the light layer.
I forget which, but be sure to set blending mode (on the layer, or sprite, eh), to either 'add' or 'multiply'.
Might take a little experimentation, but this is what worked for me when I had a lot of lights at once.
In this regard it is more akin to 'fog of war', and in fact, you should be able to do the same thing FOR fog of war.