You can certainly substitute light molasses for dark corn syrup (if that’s what the recipe calls for), as the two are quite similar. The replacement of molasses for light corn syrup will produce a pie with a stronger flavor, and may also seem sweeter. Whether the chocolate flavor in the pie is strong enough to overcome the additional taste of the molasses will depend on your taste.
How do I determine how much orange oil to use in place of grated orange peel? What would the ratio be?