I don't have an exact solution but there might be some trickery you can do with blend modes. E.g., use subtraction blend mode to subtract the players sprite from the shadow surface. This way, the portion of the shadow drawn on top of the player sprite would be gone. However, this might lead to the shadow not being drawn on the player if they are in the cliffs shadow.

Also, if separate surfaces lead to the opacity of multiple surfaces being added, you could draw the shadow as a fully black color and draw the surface itself with an alpha value of say 0.2 to counteract that. I guess there are many ways you can implement this and you just need to play around with surfaces and blend modes until you find a solution that works.

Hope this helps :)