Greek yogurt substitute in baking? So this recipe (lemon rhubarb pie), calls for 3 tablespoons of Greek yogurt. What would be a good substitute for Greek yogurt? creme fraiche or cream cheese? 
And will it affect the final product?
Given your options, I would go creme fraiche, you may need to thin with a small amount of milk or water to get to yogurt consistency.  Three tablespoons...you probably won't notice a difference.